Some of you may be bewildered by the various colours of boat rollers available. Most of this is historical and no longer relevant. 4in x 4in Wobble Roller Blue with 25mm Bore Viking Rollers 91115 Black rubber. Still the cheapest. Ok for tinnies Blue. Once hard and suitable for tinnies Red. Originally softer for fibreglass boats. Popular in QLD but now made no different to Blue (Polyurethane) Grey. Only used for wobble rollers. Most trailer manufacturers use Blue. We therefore do not stock Red. (For replacement of Red rollers, use Blue.) For ribbed wobble rollers, only use Grey. For smooth wobble rollers, only use Blue or Black. Bow Vchocks. For tinnies, use Black or Red. For fibreglass, use Red (which may go over to Blue in the future).