Description Are you looking for professional products with reasonable prices? Are you looking for a sturdy, durable and reliable seat post shim that can complete multiple tasks? If so, our products will be your best choice! Our professional seat post shim will meet your needs. Features -Color:Black -Material:Aluminum Alloy -Size:6.00X3.00X3.00cm/2.36X1.18X1.18in -Note:Converts 27.2mm to 30.9mm - Good workmanship, not easy to fade. Convert 27.2mm to 30.9mm seat post socket. - Sturdy and anti-wear aluminum alloy material, sturdy and durable to use. - Can be used as seat post tube, seat post reducer socket, seat post reducer adapter, fixed gear seat post tube. - It is simple , but very practical in use, which brings great convenience to you. - Simple in structure, easy to use, not easy to deform, you can use it with confidence. Good workmanship, not easy to fade. Convert 27.2mm to 30.9mm seat post socket. Sturdy and anti-wear aluminum alloy material, sturdy and durable to use. Can be used as seat post tube, seat post reducer socket, seat post reducer adapter, fixed gear seat post tube. It is simple , but very practical in use, which brings great convenience to you. Simple in structure, easy to use, not easy to deform, you can use it with confidence.