Bachmann HO Scale E-Z Mate(R) knuckle couplers have springs molded as an integral part of the knuckle coupler. They operate with their standard metal ′glad hand′ and an under-track magnet (sold separately). E-Z Mate Couplers feature positioned coupler heads and different shank lengths as noted, and are completely compatible with all magnetically operated knuckle couplers currently on the market. Centered shanks are most widely used on rolling stock. A variety of E-Z Mate couplers and accessories are available as replacements or enhancements to Bachmann freight cars, locomotives and passenger cars. See the entire line of Bachmann HO Scale couplers and trucks. Springs are molded as an integral part of the knuckle coupler. They operate with a standard metal ′glad hand′ and under-track magnet. They feature a center shank and are completely compatible with all magnetically operated knuckle couplers currently on the market.WARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov