The SYL-960 Floor/Track Hybrid Tripod Dollyfrom Glide Gear features interchangeable wheels for use on dolly track or straight on the floor. It is machined from aircraft grade 6061 anodized aluminum alloy to tight tolerances for precision and strength. So, although this system is strong enough to be used with rigs up to 35 lb, it is lightweight and folds up to be carried in the carry bag. Once set up, you place your tripod straight on the dolly, and you can achieve smooth tracking shots whether using tracks or on the floor. To accommodate larger tripods, the legs will extend an extra 5 inches.