INJORA 4pcs Silicone Rubber Inserts For 106-108mm 1.9" Tires
Fit Tire Outer Diameter: 106-108mm(4.19" OD)
Fit Tire Width: about 36mm
Features:

Soft and super soft, two hardness are optional
Made of silicone rubber materials, waterproof and temperature resistant
53g/pcs weight offer counterweight effect and improve stability
More superb sidewall support than regular foam to keep the shape of tires
It improves traction and grip to help your rig to ouf of tough situations

Specifications:

Material: Silicone Rubber
Size: 100*32mm (3.94*1.26in)
Weight: 53g/pcs (1.87oz)

Recommended compounds:

Green: Softest, suit for 3-5lb RC Crawlers
Blue: Medium, suit for 6-10lb RC Crawlers

Package List:
4 * Silicone Rubber Inserts