Let me start by saying I've been using the ZippGuard for about 6 months now on my daily commuter backpack. That plastic wedge design? Genius when it works. The first time I installed it on my one-way zipper laptop compartment, I yanked that zipper like a pickpocket in training - not a budge. Felt like a superhero securing my tech gear.

BUT (and it's a big but)... My two-way zipper experience was like trying to keep toddlers out of cookie jars. That twisting issue other reviewers mentioned? 100% real. After a week of commuting, I'd find the guard rotated sideways like a drunk compass, completely defeating its purpose. Had to constantly readjust - not exactly "peace of mind" material.

The removal process deserves its own horror story. Thought I'd permanently married my bag to this lock until discovering the tweezer trick (after already putting a small tear in my $150 backpack - oops). Pro tip: Watch their YouTube tutorial BEFORE installation unless you enjoy stress-induced sweating.

Where it shines? Kid-proofing. Tested it on my niece's craft bag after she turned my sister's purse into abstract art. Three days of frustrated toddler tugs later - victory! Though at $15 for two, each failed pickpocket attempt costs about $7.50 in plastic...

Final verdict? Solid B- product. Works beautifully on rigid, one-way zippers (think: camera bags). Anything else feels like forcing square pegs into round holes. If they fix the twisting issue and use less brittle plastic, we might have a winner here.