The AS 901 SM delivers high work rates and perfect handling whether on slopes, in dense growth or high grass. A Briggs & Stratton Vanguard Series 2-cylinder engine with 480 cm displacement, up to 16.0 hp and an oil and fuel pump performs in tough conditions without the risk of engine damage. Propulsion occurs via a 5-speed manual transmission with reverse gear (1.8 km/h) that covers a speed range from 1.2–4.0 km/h. The rear axle differential is permanently locked, resulting in excellent traction even on wet grass. Twin tyres ensure even greater traction and stability while a vertically installed engine provides a low centre of gravity and balanced distribution of weight, at a total of 215 kg.

The AS 901 SM is conveniently operated via four levers. Individual wheels are controlled via a patented steering and brake clutch system by which light pressure on the wheel’s respective operating lever opens the limited slip differential; full pressure activates the brake on that wheel. Furthermore, the limited slip differential is permanently locked when in drive and the automatic parking brake engages as soon as the drive lever is released. This added safety feature stops the flail mower whether on a slope or level ground. Teflon-coated stainless steel Bowden cables ensure minimal expenditure of force. The result is safe, simple, and convenient operation.

With a robust 90 cm wide flail mowing unit equipped with 26 pairs of Y-flails, the AS 901 SM is engineered for harsh conditions. The flail mower can cut grass up to 130 cm high at work rates reaching 3,600 m² per hour. The flail mowing unit is supported by pendulum bearings, delivering uniform mulching results by compensating for uneven terrain. The flails ride up and over obstacles, protecting both the engine and the operator from damage. A perforated impact guard provides additional safety.

Cutting height can be adjusted to 6 levels from 10–100 mm, while the operating bar can be conveniently adjusted laterally and in height to match both the operator and the conditions.