Have you ever been on a stability ball that makes it hard to get the right form for your exercise? This safe, heavy-duty, slow-deflate quality 65cm SPRI® Xercise Ball® feels soft but solid enough not to distract you during a workout. They are durable enough to withstand diverse training applications in any home or club environment. Professional Plus (slow-deflate up to 350 lbs.) Xercise Balls® were designed to last in all workout environments.