Features: for various models. Easy to assemble and disassemble. Replacement for old, damaged knobs. Made of high quality material, durable. 1 pair knobs replacement, contain volume and channel switch knobs, meet your needs. Specifications: Material: ABS Diameter: Approx. 0.8 for cm(Left), 0.7 for cm(Right) for GP328, GP338, GP338, GP3688, GP320, GP330, GP340, GP344, GP360, GP380, GP388, GP640, GP680 HT750, HT1250, HT1250LS, HT1550, HT1550XLS, CP040, CP140, CP150, CP160, CP180, CP185, CP190, CP200, EX500, EX600, EX600XLS, EP350, EP450, PR400, PTX600, PTX700, PTX760, PTX760 and, PRO3150, PRO5150, PRO7150. Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1 Pair Knobs