These brass fittings are designed to be used with our Anodized Aluminum Vacuum blocks. They are 1/4" Barbed Slip Fit Brass Hose Fittings. Available in the following different sizes: 1/8", 3/16", 1/4", 5/16", 3/8" and 1/2". Sold Individually. Be sure to use teflon tape to insure a leak free installation.