If you want a compact in-ear design with a touchscreen case and more total listening time for movies, choose Rulbovs Earbuds; if you need open-ear listening that leaves you more aware of nearby sounds, choose Monster Open Ear AC520. The key difference is how they sit in or around your ears, not their Bluetooth version: both use Bluetooth 6.0 and are described as low-latency options for video.
For watching at home, I’d lean toward Rulbovs for its in-ear fit, five EQ modes, and 48-hour combined playtime. Monster makes more sense when staying aware of your surroundings matters more than isolating yourself in the audio.
• Rulbovs Earbuds: In-ear design, touchscreen charging case, five EQ modes, and up to 48 hours of total playtime; trade-off: the listed 6 hours of playback per charge is shorter than Monster’s 8 hours.
• Monster Open Ear AC520: Open-ear hook design, up to 8 hours per charge, and IPX6 water resistance; trade-off: its open-ear fit does not offer the same in-ear placement, and it has no noise control.
• For movies: Rulbovs is the more appealing fit if you want in-ear listening and sound adjustments; Monster suits a viewer who wants to remain aware of nearby activity.
• For outdoors: Monster’s open-ear format is designed to let surrounding sounds through, while Rulbovs offers a stated IPX5 rating against sweat and spray.
• Choose Rulbovs if the touchscreen case, EQ choices, and longer combined battery figure matter most.
• Choose Monster if open-ear awareness, a hook-style fit, or its higher stated water-resistance rating matters more.
Rulbovs is the more feature-heavy choice if you like having controls and information available without reaching for your phone. Its charging case has an LCD touchscreen for checking battery levels and the time, changing wallpapers, controlling playback and volume, and using a remote-photo function. It also includes a Find My Earbuds option and mini-games. Those extras are distinct from the core listening experience, but they may appeal to someone who enjoys hands-on controls.
The earbuds themselves use an in-ear design, with touch controls for playback, calls, volume, track changes, and voice-assistant access. Bluetooth 6.0 is described as supporting a stable connection and low-latency audio for movies and gaming. Five EQ modes—Standard, Rock, Pop, Classic, and Jazz—give you a few ways to adjust the sound profile. For a movie viewer who wants to try different settings for dialogue, music, or general listening, those presets offer more choice than Monster’s listed feature set. They are presets, though, not a promise that every movie will sound a particular way.
How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-23 · 8 min read · Independent comparison
Who should skip it: Skip Rulbovs if you specifically want an open-ear fit that keeps nearby sounds accessible, or if you need more than 6 hours of listening from the earbuds between charges.
Monster Open Ear AC520: Who It's For
Monster takes the opposite approach to Rulbovs: the AC520 uses an open-ear hook design rather than placing the earpiece in the ear canal. The product information describes a fit shaped around the natural curve of the ears, and the feature list emphasizes awareness of surrounding sounds. That can make it a more natural match for an office, walk, or other setting where you want to listen while remaining open to conversations and activity around you.
Monster’s battery figures are 8 hours on a single charge and up to 24 hours with the case. The case uses a slide-open design and is described as having a removable lanyard. The AC520 is rated IPX6 for water resistance against sweat and rain, and its listed recharge time is 2 hours. Those details point toward a listener who wants a wearable open-ear design for daily activity and values awareness and water resistance more than a large number of case-added hours.
Who should skip it: Skip Monster if you want in-ear earbuds, noise control, or a touchscreen case with listed playback and EQ controls.
• Best for in-ear listening → Rulbovs Earbuds. Its earpieces sit in the ears, unlike Monster’s open-ear hook design.
• Best for staying aware of nearby sounds → Monster Open Ear AC520. Its open-ear format is specifically described as allowing awareness of surrounding activity.
• Best for total stated playtime → Rulbovs Earbuds. The listed combined figure is up to 48 hours, compared with up to 24 hours for Monster.
• Best for longer single-charge listening → Monster Open Ear AC520. Its stated 8 hours per charge exceeds Rulbovs’ 6 hours.
• Best for adjusting sound with presets → Rulbovs Earbuds. It lists five EQ modes; Monster’s provided features do not specify EQ presets.
• Best for water resistance by the listed ratings → Monster Open Ear AC520. It is rated IPX6, while Rulbovs is rated IPX5 against sweat and spray. Neither rating means the earbuds should be submerged.
• Best for hands-on case controls → Rulbovs Earbuds. The LCD screen provides a range of functions beyond charging, including battery and time display, playback controls, and Find My Earbuds.
• Best for a removable lanyard and slide-open case → Monster Open Ear AC520. Its case is described with a slide-open mechanism and removable lanyard.
For movies, the trade-off is straightforward. Rulbovs gives you an in-ear fit and EQ options, while Monster prioritizes an open-ear experience. Both list Bluetooth 6.0 and low-latency listening, so the stronger deciding factor is whether you want to focus on audio in your ears or keep more awareness of the room around you.
My Verdict
That recommendation is for someone comfortable with in-ear earbuds, not a claim that Rulbovs will suit every listener. If awareness of nearby sounds is the deciding factor, I’d choose Monster instead.
Before deciding, think about where you’ll use the earbuds most. A movie watched in a quiet room creates different needs from a film playing while you work or move around. Rulbovs’ in-ear design and EQ choices suit a more focused listening setup. Monster’s open-ear construction is aimed at keeping you aware of your surroundings, but that means it is not the pick for someone seeking noise control.
Also separate single-charge playback from total playtime. Rulbovs lists 6 hours per charge and up to 48 hours with its case; Monster lists 8 hours per charge and up to 24 hours with its case. The larger combined figure does not mean Rulbovs lasts longer between charges. If your listening sessions are long and you don’t want to pause to recharge the earbuds, Monster has the longer stated single-charge figure.
Water resistance is another practical distinction, especially for commutes or workouts. Rulbovs lists IPX5 protection against sweat and spray; Monster lists IPX6 water resistance and describes use around sweat and rain. These ratings offer a useful comparison, but neither product’s details support treating the earbuds as suitable for submersion.
Finally, consider whether the extra controls matter to you. Rulbovs puts multiple functions on the charging-case touchscreen and provides touch controls on the earbuds. Monster’s described strengths are its open-ear fit, case design, lanyard, and surrounding-sound awareness. If sound customization and on-case information would go unused, those Rulbovs features may not influence your choice. If you rarely need a case screen but value open-ear listening, Monster is the more direct fit.
Rulbovs is the stronger fit if you want in-ear listening and five EQ modes. Monster is a reasonable alternative if you prefer open-ear listening and want to remain aware of nearby sounds. Both list Bluetooth 6.0 and low-latency audio for video.
Monster lists up to 8 hours of playback on a single charge. Rulbovs lists 6 hours per charge, though its case brings the stated combined total to up to 48 hours compared with Monster’s up to 24 hours.
Rulbovs is an in-ear design and lists active noise cancellation in its product information. Monster has an open-ear design and lists no noise control, so it is intended to keep surrounding sounds accessible rather than block them.
Monster lists IPX6 water resistance and is described for use around sweat and rain. Rulbovs lists IPX5 protection against sweat and spray. Neither should be submerged, and the stated resistance ratings do not establish identical protection in every situation.
• chalvh Ear buds vs Atheewon Headset: Ipx7 Waterproof Earbuds
As an Amazon Associate I earn from qualifying purchases.
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
When you buy through links on this page, we may earn a commission from qualifying purchases at no extra cost to you.
Amazon and the Amazon logo are trademarks of Amazon or its affiliates. This site is an independent third-party review and is not affiliated with, endorsed by, or sponsored by Amazon or the product brands mentioned.