Amazon.com: RevTime Easy DIY Interlocking Outdoor Rubber Tiles 20" x 20" x 1” Thick for Playground Use, Outdoor Gym Floor, Sports Deck, Backyard Play Area, Safety Rubber Paver (Pack of 4) Green :
Commercial Playground Equipment - Swing Accessories - Wear Mats - American Parks Company
Rubber-Cal 19.5-in W x 19.5-in L x 2.5-in T Interlocking Rubber Gym Floor Tile (11-sq ft) (4-Pack) in the Gym Flooring department at Lowes.com
Amazon.com: IncStores 2 1/4 Inch Thick Outdoor Playground Mat | Extra Thick Rubber Mat for Grip and Safety Around Backyard Swings, Slides, and Jungle Gyms | 32" x 54", Earth : Toys & Games