This Remote-Controlled Electric Skid Steer-both the four-wheeled Elise 900 and the tracked Mini Z400-can be operated from outside the machine via smartphone app. Both models run off rechargeable lead-acid battery-powered electric motors (vs. diesel engine), which means minimal maintenance, low noise level, and no exhaust emission, allowing safe use indoors. As to attachments, both machines accommodate the company's (some 40) or universal quick-attaches made for skid steers. Elise900: Three motors-two for motive power, one for the hydraulic pump. Each wheel has a planetary gearbox that reduces high motor speed down to travel speed, which ranges from 1 to 8 mph. Batteries reportedly last up to 8 hours, with recharging to 80% in 3 hours and 100 percent in 51/2 hours. Load height is 12 feet, load capacity is 2,000 pounds, tipping load is 4,000 pounds. Mini Z400: Features 15 hp power, 165-foot operating radius, two joysticks, secondary controls, and emergency stop. Travel speed ranges from 1/2 to 3 mph. Battery longevity and recharging times reportedly similar to the Elise 900. Load capacity is 880 pounds, tipping load is 765 pounds.