Over 20 years ago Berkey System revolutionized they way that rigs were built and here's the series that started it all - the 500 Series! The 500 Series is based on 1/2 inch diameter tube. Very strong. The 500 Series has all your favorite style of blocks; right angle blocks, parallel blocks, accessory mount blocks, split blocks, linear and rotational blocks, linear movers and more. All 500 Series tubing is centerless ground for excellent fit. As with all other Berkey System the 500 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.