ADAPTOR CHAIN DOUBLE SECURITY AGAINST BIKE THEFT It could hardly be simpler – with this hardened steel frame lock chain, you have an ideal extra protection for your bike. The frame lock chain CHAIN from ABUS makes it extra easy to double lock your bike. You just need to wrap the chain around a fixed object, pull the chain end with the lock through the ring in the chain, and then lock it in the lock housing. You don't need an additional key, and it's also not necessary to lock the shackle separately. The frame lock chain CHAIN is compatible with ABUS frame locks 4960, 5850, 5650, and 5950.