Check the listing for details. Orange Carboy Cap. Condition: New. Listed at 2.99 USD. Standard orange carboy cap to fit all 3, 5, 6 and 6.5 gallon glass carboys (except 6.5 gallon Italian carboys). It securely snaps on the mouth of the carboy and has 2 ports for use with blow-off tubes, airlocks and racking canes. Compatible Carboys: - Fits all common 3, 5, 6, and 6.5 US gallon glass carboys with an outside mouth diameter of 2-1/8in (see exception below) - Fits 3, 5 and 6 US gallon Vintage Shop plastic carboys- Does NOT fit 6.5 US gallon glass carboys with the threaded mouth made in Italy Compatible Racking Canes: - Fits 3/8in OD plastic racking canes only Compatible Airlocks: - Fits standard 3-piece or double-bubble airlocks Compatible Blow-Off Tubes: - Fits blow-off tubes with an inside diameter of 5/8in on the center port or 7/16in on the side port. Details: Overall Outside Width:2-1/8in (6.4cm) Overall Height:3-5/32in (8cm) Center Port Inside Diameter:3/8in (10mm) Center Port Outside Diameter:5/8in (16mm) Side Port Inside Diameter:9/32in (7mm) Side Port Outside Diameter:7/16in (11mm) Material:Rubber