After some rain, it doesn't unlock easily, but I sprayed it with WD40 and it has been working fine for the past year. For its price, it's great. It's not a chain, it's a wire rope that is found inside metal and plastic cylinders with an outer membrane

From the first month, the locking mechanism started to break, eventually needing WD spray, a second key, and twenty minutes to open before throwing it in the trash