Hardened, tempered chrome-plated & polished. Knurled bands for a positive grip. Spring-loaded ball bearing ensures secure fit. Available in 1/4", 3/8" and 1/2" square drive sizes. 1/4" set includes 50, 75 and 150mm extension bars. 3/8" and 1/2" sets include 75, 120 and 250mm extension bars. Weight: 0.9259415004 Pounds. Manufacturer: SLTL4.