Over 20 years ago Berkey System revolutionized they way that rigs were built and along with the 500 Series, the 750 Series was right there doing the heavy rigging. The 750 Series is based on 3/4 inch diameter tube. Very strong. The 750 Series has all your favorite styles of blocks; right angle blocks, parallel blocks, accessory mount blocks, split blocks, linear and rotational blocks, and more. All 750 Series tubing is centerless ground for excellent fit. As with all other Berkey System the 750 Series can be interfaced with all of the other series of components through the use of bushings. Berkey System components are made from 6061 aluminum and are black anodized for durability. All Berkey System products are made in the USA and are covered by our Lifetime Warranty. See Terms and Conditions for details.