Replacement trampoline bed (the black circle) for circular trampolines 13ft in diameter manufactured by Plum Products & is the highest quality American made Grade A Permatron jump mat complete with highest quality vrings to attach springs. These jumping mats should not be compared to cheaper & rougher mats which are commonly low quality with rough surfaces which can lead to friction burns to a youngsters skin. The Plum Products trampoline jump mat is highly calendered & results in the mat having an extremely hard wearing & smooth surface & classed as a Grade A jumping mat. Suitable for all 13ft circular trampolines with: 88 x 7 inch (178mm) springs.NOTE: To measure the size of your sping & trampoline, see the images above.