THIS IS A NEW 3-7/8" (CALLED 4") BILLET ALUMINUM BLOWER SNOUT,THIS HAS THE LARGE 1-1/4 HOLLOW HARDENED SHAFT,IT WORKS ON MOST BLOWERS 3-71,4-71,6-71,8-71,10-71,12-71 & 14-71,IT FITS MOST BRANDS SUCH AS GM,WEIAND,LITTLEFIELD,MOONEYHAM,BOWERS,BDS,& OTHERS.IT HAS A 2"PULLEY SHOULDER,IT HAS THE SQUARE IN END OF SHAFT TO ROTATE ENGINE,IT INCLUDES COUPLER & BOLTS,WE HAVE SOLD HUNDREDS,IT IS A NICE PIECE.PLEASE SEE MY OTHER AUCTIONS,WE ALSO HAVE A 5" & A 6" LISTED THANKS BOB