Product description rings are special tools oil drilling, geological prospecting and other departments for hanging elevator's. Excellent selection, rugged, wide application, the use of advanced forging and heat treatment technology and strict testing and non-destructive testing of strength, with excellent quality. Materials using premium quality alloy structural steel design safety factor n = 2.25 ~ 3. Rated load: 75 ~ 750USton. Two arm rings for die forging, free forging stretching intermediate lever. Forging a special heat treatment. 100% non-destructive flaw detection. Arm rings have been 1.5 times the rated working load factory load test. Rated load and logo on the arm rings. Arm rings coated finished paint. Suitable for deep and ultra-deep drilling operations. This arm rings in pairs. Model D r1 R1 L1 L2 L3 r2 R2 L4 L5 L6 L weight DH75 53 21 53 20 106 150 29 80 70 140 203 1500 90 DH150 68 24 51 25 102 150 29 64 95 140 210 1800 165 DH250 78 31 70 30 140 200 35 102 135 203 250 2700 346 DH350 89 37 70 35 140 203 35 102 135 203 254 3300 462 DH500 115 48 83 50 170 250 48 121 160 242 300 3600 890 DH750 140 56 127 55 190 318 63 131 190 262 330 3660 1400