Japaneses saddles made with fibreglass trees for a superb fit for both horse and rider.
 
Various weights and size are available. 
Saddles with a  foam underside are typically lighter than those made with the harder wearing fabric.
 
Saddle that weight 1+ kg are made with leather on the underside.
 
Fiberglass Fabric S 320g
Fiberglass Fabric M 373g
Fiberglass Fabric L 600g
 
Fiberglass Foam S 190g
Fiberglass Foam M 210g
 
Fiberglass Leather  1kg
Fiberglass Leather  1.5kg
Fiberglass Leather 2.5kg