SB packaged, Ø 6 mm, black hardened steel links with stainless steel alloy, protective hose and housing included, mechanical locking type, controllable via app, battery-free and keyless, easy to unlock via NFC technology using the app, secure data transfer using cryptographic technology as in mobile payments, shareable via the app - friends can be added to the account, usage and unlocking location can be tracked, two lock variants available in two colors each, reliable and robust locking system with strong chain, environmentally friendly without batteries thanks to NFC technology and muscle power, recommended for bicycles Diameter 6.0 mm Closing method smartphone Type/kind Item Chain lock design Safety high