PLEASE MEASURE FILLER NECK BEFORE PURCHASE! Female Fitting, Vented Non-Locking, 2 1/2" Nominal Size, 11.5 Threads/Inch, For diesel applications only Nominal Size: 2-1/4" Safety chain and crossbar are standard Across Threads - Filler Neck 2-5/16" Across Threads - Cap 2-1/4" Replaces: Velvac 600135, Tectran 91-8100, Tramec Sloan 431084