Siemens Kleinfräsen K4 and K4-A (Klein = small), 4 hp two stroke petrol engine model 92068-0FM2, ca. 1925-1927. Working width 70 cm, 12 spring tines with 500 mm, rotating at 210 rpm. The engine bore and stroke are 85 x 95 mm. The carburettor was a SUM KMH 28 ru.

These seem to be some sort of conversions from the Siemens K4, probably made in Switserland. No further details available.

Siemens Kleinfräse K5 and K5-4, 2 stroke petrol engine, developing 5 hp at 1500 rpm. The K5 had engine model 92168-1FM2, the K5-4 had engine model 3FM2. Made from 1928 till 1935, Siemens was able to sell around 5000 of the K5. Fuel consumption 3 - 4 litres/hour. Working width was max. 70 cm, with it's speeds of 1 and 2.5 km/h the K5 could work 600 or 1500 m3/hour. With use of rubber street rings, a speed of 5 km/h could be reached for transportation purposes. The machine weighed 250 kg and cost 1630 ReichsMark in 1928.

The carburettor was a SUM KMH 32. A difference between the K5 and the K5-4 is that the K5-4 no longer had a removable cover above the clutch, meant for lubricating. The engine bore and stroke are 90 x 95 mm. The latest machines were available with oil bath air filter, and wheel release clutches operated by a handle in the wheel hubs.

With many improvements, this tiller's manufacture was continued by Bungartz until ca. 1945.