These seat post shims have an alloy construction, and are all 80mm in length. Their outer diameters vary, as shown below.
Features
Alloy
Mount to seat tube
All seat post shims have an inner diameter of 27.2mm
All seat post shims are 80mm in length
SEA4605: 27.2mm ID x 28.6mm OD
SEA4607: 27.2mm ID x 29.2mm OD
SEA4609: 27.2mm ID x 29.8mm OD
SEA4611: 27.2mm ID x 30.0mm OD
SEA4613: 27.2mm ID x 30.2mm OD
SEA4615: 27.2mm ID x 30.9mm OD
SEA4615: 27.2mm ID x 31.6mm OD