... :P504A-BV1.0/1.2 P means plastic feed frame,casting feed frame without "P"504 is the code for wire feed ... frame we have 21,401,402,404,501,502,504,P504 ... ø30,"B"means the roll diameter is ø40V is the type of roll ,we have V,U,K,Three types,"V ... .0/2.4the drawing of the P504A: Plastic casting feed frame