The B&G 6″ Plastic Crack-Crevice Extension Straw (5700-B) fits into the Multeejet Crack & Crevice Tip B&G Part 5800-CC that is part of the Multeejet C&C Tip Assembly (complete) B&G Part 5850-CC . See the B&G Pest Control Catalog in the Product Documents section below for more details and spare parts drawings.
B&G Multijet Crack and Crevice Tip Extension 5700-B BG2037 Review