Many users neglect to use "safety clips" when using 2-lug Universal Ends so these have a special locking collar that prevents accidental disconnection. Typically they can be installed at the compressor or manifold where they are off the ground and stationary (it should be noted the heads are physically bulkier and larger than traditional universals, which is not ideal in some applications). The heads interchange with all 2-lug universals, replacement gaskets do NOT interchange.