Rufus Dawg Aluminum 2 Pc. Drop Forward System with Removeable Dovetail is the most universal drop on the market. This innovative and stylish upgrade works flat mount or dovetail ASA's ( Air Source Adapter). For flat mount ASA's use the Drop alone, for Dovetail ASA's add the included Dovetail Mount. The system is made from Aircraft grade aluminum and relocates your tank adapter (ASA) forward and down to improve the balance and feel of your marker.