Features:

Extra protection for your seat post: Protect the seat post gap form dust, water, sand and mud; Avoid seat post surface scratching due to foreign material intrusion
2 size options for your selection with 25-30mm that covers 25.4/27.2mm and 30-35mm that covers 30.4/30.8/30.9/31.6/33.9mm seat post diameter
Multiple color options for your selection to match your bike style
Also could be used as seat post travel indicator for re-positioning seat post.
Sold as 2 pcs / PACK (enough for 2 bikes installation) at the side and color you choose n

Package includes:
2 pcs of seat post silicon rings at the size and color you choose