Tri-Grip Rubber Weight Plate/Commercial Gym Equipment

Bumper weight best size for:

10lbs-5kg:   teaching olympic lifts and for women or teenagers            

15lbs-7kg:   Same uses as the 10s, but this offers greater durability at only a slightly heavier weight 

25lbs-11kg:  A Very popular weight as they are very durable and throwing these on an Oly bar gives you 95 pounds (Fran Rx)

35lbs-16kg:  A great size for adding more weight on the bar 

45lbs-20kg:  The most popular size for gyms- 45's really let you load up your bar and make some serious strength gains