Spring of coiled steel inside an Aluminum seat post is the low cost end of the market.. saddles can wobble rotationally a bit..
Thud Busters are not light but they do dampen road shocks effectively with a series of rider's weight adjustable elastomers, (mine are for my 200#)
Newer 'Body Float' is Active and follows the up and downs with 2 coil springs..
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Last edited by fietsbob; 03-20-17 at 11:13 AM.