KROIS digital couplers are compatible with many other model railway couplers and fit every car with a NEM 363 coupler pocket. The couplers can be used with voltage from 12V to 22V and can be released up to 10 seconds. Permanent electric contact destroys the coupler, please use a digital decoder with time control! Suitable couplers: Roco Universalkupplung (universal coupler), Märklin Kurzkupplung (close coupler) with brass bracket or Krois Close Coupler MK