Seachoice Bow Rollers are designed to support the weight of your boat and aid in launching and loading your boat. Our boat rollers are made of TPR (Thermal Plasticized Rubber), which is resilient, non-marking, stronger than black rubber, and softer than polyurethane. Seachoice is committed to delivering quality marine accessories and OEM replacement parts to satisfy fishing, boating and watersports enthusiasts worldwide. Seachoice is run for and by boaters, offering a wide-ranging product line while remaining affordable. Made in the USA. Designed to support the weight of your boat on the trailer; absorbs road shock Aids in launching and loading your boat TPR (Thermal Plasticized Rubber) is resilient, non-marking; stronger than black rubber and softer than polyurethane Made in the USA Attributes Length 4" Hole 1/2" ID Pkg. Bulk Case 12 Diameter: Hole 1/2" ID