Just got this Sonew copper lock cylinder and wanted to share my thoughts. First off, the build quality feels super solid - that H59 copper material is no joke. It's got a nice weight to it and the finish looks premium.

The dual open mechanism works smoothly, and I appreciate the anti-rust properties. Tested it with some water exposure (accidentally!) and no issues so far. The keys turn smoothly without that gritty feeling you get with cheaper locks.

BUT... major warning about returns! Saw a review saying UPS charged $300 for return shipping, which is insane. Definitely measure twice before ordering because you might be stuck with it if it doesn't fit.

Overall though? For the price, this seems like a quality upgrade from standard lock cylinders. Just make absolutely sure you're getting the right size before clicking buy!