If you want to restore the locking mechanism on your BAKFlip MX4 or G2 and need durable metal-and-plastic knobs for a secure seal, choose BOXOB 2pcs; if you need a complete set of four upgraded clamps to stop rattling and stabilize the prop rods on a thickened tonneau cover, choose Purthog 4PCS. This isn't about which brand has a fancier logo; it is strictly about whether your off-roading rig needs a fresh lock or a solid hold.
• BOXOB 2pcs: The biggest strength is its robust construction using quality metal and plastic designed specifically to replace worn lock knobs on BAKFlip systems, ensuring smooth operation. The trade-off is that it only includes two pieces, so you will need to buy two sets to cover all corners of a standard bed. This pick is for the DIYer who has lost a specific knob and needs a direct replacement for their cargo box cover.
• Purthog 4PCS: The standout feature here is the quantity and the upgraded clamping design that actively reduces displacement and minimizes rattling during rough movement. The trade-off is that these are specialized clamps for the support rod, not functional locks, and they require precise installation into a 0.3-inch diameter rod. This pick is for the truck owner dealing with loose covers that flap or shake while driving over uneven terrain.
The BOXOB 2pcs kit is a surgical fix for a very specific problem: a broken or missing lock knob on a BAKFlip MX4 or G2 tonneau cover. When you are out on an off-road trail, the last thing you want is a tailgate that won't stay shut because the locking mechanism has failed. These replacement parts are engineered to restore that function immediately. They are not just generic plastic bits; the manufacturer specifies a blend of good quality metal and plastic that is hard, reliable, and resistant to deformation. This suggests a component built to handle the vibration and stress of a vehicle in motion without snapping under pressure.
The physical dimensions tell you exactly what you are getting. These measurements align perfectly with the original specifications required for the BAK system to operate smoothly. If your current knob is stripped, cracked, or simply gone, this part fits like it was made for the job.
You should buy this if you own a compatible BAKFlip model and have a single point of failure in your locking assembly. It is ideal for car enthusiasts who prefer to fix issues themselves rather than paying for dealership service. However, you should skip this product if you are looking for a full upgrade of your entire cover system or if you need more than two knobs. Since the package contains only two pieces, you might find yourself needing to purchase another set if both sides of your cover suffer from wear simultaneously. It is a targeted solution for a targeted problem.
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-11-08 · 6 min read · Independent comparison
The Purthog 4PCS set addresses a different pain point entirely: the annoying rattle and instability of a tonneau cover that doesn't sit tight against the truck bed. When you are driving off-road, the wind and vibration can cause the cover to shift, leading to noise and potential damage to the fabric or the frame. These clamps are designed to solve that by providing powerful clamping force on the support rods. The grooves inside the clamp conform to the rod, effectively reducing displacement and cushioning the impact during vehicle movement. This means less noise in the cabin and less wear on your cover hardware.
Durability is a major selling point here. Crafted from thickened high-density plastic, these clamps resist brittleness even after prolonged exposure to harsh elements like direct sunlight and heavy rain. Unlike cheaper alternatives that might crack after a few seasons, this material is built to withstand stress impacts from vehicle vibrations without fracturing. The package comes with four units, which is the standard number needed to secure the main support structure of most tonneau covers. Having a full set ensures that every rod is stabilized, preventing any single weak point from causing the whole cover to sag or flap.
This product is perfect for owners of thickened tonneau covers who notice their support rods shifting or rattling. It is also a smart choice for those who want easier maintenance and cleaning. The upgraded design allows for easier disassembly compared to older, stuck-on styles, making it simple to remove the cover when you need to access the bed fully. However, you must verify that your support rod diameter is exactly 0.3 inches before buying. These clamps are not universal; they fit a specific size. If your rod is slightly thicker or thinner, these will not work. Also, be prepared to do some careful filing if the latch slot on your existing cover is too narrow to slide the new clamp on easily.
• Best for restoring a broken lock: Choose BOXOB 2pcs if your issue is a missing or damaged knob that prevents the cover from closing securely.
• Best for eliminating rattles: Choose Purthog 4PCS if your cover is closing fine but shaking, flapping, or making noise while driving on bumpy roads.
• Best value for a full set: Choose Purthog 4PCS because you get four clamps in one package, covering all necessary points without needing multiple orders.
• Best for durability in harsh weather: Both are strong, but Purthog's thickened high-density plastic is specifically highlighted for resisting brittleness from sun and rain exposure.
• Best for compatibility with BAKFlip MX4/G2: Choose BOXOB 2pcs as it is explicitly designed to match the dimensions and function of those specific models.
• Best for ease of maintenance: Choose Purthog 4PCS due to the enhanced design that facilitates easier removal for cleaning and repairs.
• Best for off-road stability: Choose Purthog 4PCS because the reduced displacement and cushioning directly address the vibrations experienced during off-roading.
• Best for simple replacement: Choose BOXOB 2pcs if you know exactly which part is broken and just need a drop-in replacement for that specific component.
In my opinion, I would choose the Purthog 4PCS set for general use, especially if you plan to take your truck off-roading regularly. While the BOXOB knobs are excellent for fixing a specific lock issue, the Purthog clamps offer a more proactive improvement to the overall ride quality of your truck bed cover. Stopping the rattle and securing the prop rods provides peace of mind that goes beyond just keeping the cover closed; it keeps the entire system quiet and stable under stress. That said, if your specific problem is a broken lock on a BAKFlip, then the BOXOB 2pcs is the only logical choice. But for a comprehensive upgrade to how your cover behaves on the trail, the four-piece set wins.
Using them on a different size could result in a poor fit or damage.
Installation instructions suggest that if the opening is too narrow, you may need to enlarge the latch slot using a rat-tail file to slide the component on fully.
No, they are made of a combination of good quality metal and plastic, which provides a balance of hardness and reliability without being overly heavy.
The package contains 4 tonneau cover clamps, which is typically the correct number to stabilize all support rods on a standard tonneau cover.
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