In 1999, The Rock Slide invented the first ergonomic slide which has been favored by professional acoustic and electric players ever since. The signature is a tapered interior design, which fits like a glove. Other features include the knuckle cutaway for finger flexibility and the dished finger rest for perfect control and vibrato. Large Rock Slides are one of the heaviest on the scene. This makes for killer sustain on the thickest of string gauges and a down-right dark sound. 21.5mm I.D. 59mm long 100g. USA Ring size 11-12.The Rock Slide Item No. TRS-LBShop like the pros at Sam Ash Music, where discerning musicians go for premium guitar accessories.