We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-29 · 7 min read · Independent comparison
If you want a hard-shell home for your Sony WF-C510, WF-C700N, WF-C710N or WF-C500 charging case, choose RLSOCO Carrying Case; if you need to keep silicone-tip earbuds physically tethered to you during runs and commutes, choose Podstring Anti-Lost Strap. These two products are often compared because both live in the "charging case earbuds" world, but they solve completely different problems. One is a storage and protection shell. The other is a 0.6g elastic leash that stays attached while your earbuds sit in their case. If you are torn, the deciding question is simple: are you protecting a case, or are you preventing a drop?
• RLSOCO Carrying Case — biggest strength: Custom-molded fit for specific Sony models, with a hard EVA shell rated water-resistant, dust-resistant and shock-resistant.
• RLSOCO Carrying Case — biggest trade-off: It is case-only, it fits a narrow list of Sony models, and it does nothing to stop you dropping a loose earbud mid-run.
• Podstring Anti-Lost Strap — biggest strength: At roughly 0.6g with a 0.65mm elastic cord, it keeps earbuds tethered and stays attached inside the charging case while you charge.
• Podstring Anti-Lost Strap — biggest trade-off: It attaches through silicone ear tips, so it will not work with open-ear designs or AirPods 1/2/3/4, and it offers zero impact protection.
• Who RLSOCO is for: Sony WF-C510 / WF-C710N / WF-C700N / WF-C500 owners who want a dedicated, protective travel and storage shell.
• Who Podstring is for: Runners, cyclists and commuters using in-ear earbuds with silicone tips who keep losing or nearly losing a bud.
The RLSOCO Carrying Case is a purpose-built shell, not a universal pouch. It is customized for the Sony WF-C510, WF-C710N, WF-C700N and WF-C500 true wireless models, which means the interior is shaped around those earbuds and their charging case rather than being a one-size-fits-most bag. That is the whole point: a fitted case holds the charging case still instead of letting it rattle around, and it keeps the lid and hinge area from being crushed in a backpack.
The materials are the other half of the story. RLSOCO uses high-density EVA plus polyester fiber, and the brand states the fabric, lining and EVA compartments are certified to RoHS/SGS standards. The shell is described as water-resistant, dust-resistant and shock-resistant, and RLSOCO notes it uses a thicker grade of EVA specifically so the case does not deform easily. There is also a two-year warranty covering manufacturing defects, which tells you the company expects the shell to survive daily abuse.
Who should skip it: if you own earbuds outside the four listed Sony models, this is not your case. And if your actual fear is dropping an earbud while running — not protecting the charging case — a shell does nothing for that. Also note it is case only: earbuds and accessories are not included.
Podstring Anti-Lost Strap: Who It's For
Podstring approaches the same category from the opposite direction. Instead of containing your earbuds, it tethers them. The strap weighs about 0.6g, and the cord is 0.65mm elastic — thin enough that it disappears in use, which is why the brand frames it as an alternative to bulky neckbands. It attaches through the silicone ear tips of your earbuds, which is the key mechanical detail: no silicone tips, no attachment.
That attachment method makes it compatible with AirPods Pro 1, 2 and 3, plus Sony, Beats, Samsung, Bose, JBL and other in-ear wireless earbuds that use silicone tips. It is explicitly not compatible with AirPods 1, 2, 3 or 4, or any open-ear earbud without silicone tips. If you are unsure which camp you are in, check your earbuds — if they have a removable silicone tip, Podstring is designed for you.
The feature that separates it from most lanyards is charging. The strap stays on while your earbuds sit in the charging case, so you do not have to peel it off and reinstall it every time you top up. For someone who charges daily, that removes the single most annoying thing about earbud straps. The trade-off is real, though: this is anti-loss protection, not impact protection. It will not cushion a drop onto concrete or keep dust and water off your case. It is also one strap for a pair of earbuds, and the polyester sleeve is a hard-shell form factor, so it is meant to be worn, not stored away.
Who should buy it: runners, cyclists, gym-goers, commuters and travelers who want a barely-there leash and hate the ritual of removing a strap before charging. Who should skip it: open-ear users, non-Pro AirPods owners, and anyone whose main concern is protecting the charging case itself.
• Best for protecting the charging case → RLSOCO Carrying Case. EVA shell, water-, dust- and shock-resistance, and a fitted interior for four specific Sony models.
• Best for preventing a dropped earbud → Podstring Anti-Lost Strap. A 0.6g tether that keeps buds attached to you, not to the ground.
• Best for charging convenience → Podstring Anti-Lost Strap. Earbuds stay attached in the charging case, so there is no remove-and-reinstall cycle.
• Best for travel and storage → RLSOCO Carrying Case. Compact enough for a pocket, purse or backpack, and it holds the case rather than your ears.
• Best for running, cycling and workouts → Podstring Anti-Lost Strap. Built around active use, with a slim cord instead of a bulky neckband.
• Best for Sony WF-C510 / WF-C710N / WF-C700N / WF-C500 owners → RLSOCO Carrying Case. The fit is model-specific by design.
• Best for AirPods Pro and other silicone-tip in-ears → Podstring Anti-Lost Strap. Broad brand compatibility, as long as your earbuds use silicone tips.
• Best if you want both problems solved → buy both. They do not overlap. One protects, one tethers.
If I had to pick one for the average charging-case earbud owner, I would buy the RLSOCO Carrying Case. In my opinion, protection is the harder problem to solve after the fact — a cracked case or a crushed hinge is not something a strap can undo, and the fitted EVA shell, dust and water resistance, and two-year defect warranty make it the more consequential purchase for a Sony owner. That said, I would add the Podstring Anti-Lost Strap without hesitation if I ran, cycled or commuted with silicone-tip earbuds, because the stay-attached-while-charging design removes the one annoyance that makes most lanyards get abandoned in a drawer. Match the product to your actual failure mode, not to the category.
how to charge earbuds case
Put the earbuds in the charging case and connect the case to power the way the manufacturer specifies — typically via the case's own charging port or a wireless pad. The relevant difference here is the Podstring Anti-Lost Strap: it is designed so your earbuds stay attached while they sit in the charging case, so you do not need to remove the strap before charging. The RLSOCO Carrying Case is a separate outer shell, so you would take the charging case out of it to charge.
how to charge case without earbuds
You can charge the case on its own; the earbuds do not need to be inside for the case itself to take a charge. If you keep the Podstring strap on, the earbuds stay tethered to each other whether they are in the case or not, which makes it harder to misplace a single bud while the case charges separately. The RLSOCO Carrying Case does not affect charging at all — it is a storage shell around the case, not a power accessory.
how to charge jlab earbuds case
JLab is not on the RLSOCO compatibility list — that case is customized for the Sony WF-C510, WF-C710N, WF-C700N and WF-C500 only. JLab is, however, named among the brands the Podstring Anti-Lost Strap works with, provided your JLab model is an in-ear design with silicone ear tips. Charge the JLab case per JLab's own instructions; the strap does not change that process.
how to charge apple earbuds case
For AirPods Pro 1, 2 or 3, the Podstring strap is designed to stay on while the earbuds are in the charging case, so charging does not require removing it. Note the compatibility limit: Podstring is not compatible with AirPods 1, 2, 3 or 4, or open-ear earbuds without silicone tips. The RLSOCO Carrying Case is not made for Apple models at all — its fit is Sony-specific.
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