Different Size: Thanks to these lightweight plates you can slowly increase your weight bearing load by putting on an extra 0.25LB to 5 LB. The plates have 2-inch center holes and will fit on Olympic barbells and 1-inch barbells with an Olympic sleeve adapter. FOR EVERYONE: Low weight increase is good for toning and building muscle tissue, steadily over time. People who are new to the gym or weight training need to be able to easily and quickly increase weights without hurting themselves, while the more experienced weight lifters will need it for that extra push to increase that muscle burn.USE ON A BARBELL OR SEPARATELY: The plates can be put on a barbell to slowly increase the weight when doing home exercises such as bench press or military press. The plates can also be used separately. For example, you can hold the weight in your hand when doing squats or raise it above your head training at the gym. NOTE OF CAUTION: Always consult your doctor before starting any fitness program. If you feel pain or discomfort while exercising, discontinue workout immediately and see your medical provider.