This EH series is interchangeable with the Faster 4BD4FH Spare Part Kit and Faster 4BD4FH Accessories. Steel Product. This pioneering cast iron block was the first of its kind to enable the rapid connection and disconnection of attachments for skid steer loaders and similar construction machinery. It utilizes cartridges that incorporate the full benefits of flat face coupler series technology, including a decompression feature for safe coupling even with residual pressure on both sides of the circuit. The block accepts both 1/2" and 3/4" cartridges, with the larger size providing a higher flow capacity while maintaining the same compact footprint.