Please scroll through the pages, vents are listed in code order which generally means 455x160 vents first page 1, 230x160 brass page 1 & 2,  230x75 vents page 2 & 3, 455x75 vents page 3, 390x190 block vents page 3 & page 4, 230x160 spark arresters on page 4 & 5, block vent spark arresters on page 5. You can change search parameters if you wish.