Improve traction – with our robot lawn mower spikes, there are no more holes in the lawn, it's easier to drive on hills, and it won't slip on rainy days. 205 mm in diameter and 2 mm thick. Stainless Steel Material - Our robotic lawnmower tips are made of 304 stainless steel and polished in an extra production step to achieve a perfect appearance. All edges of the traction improvement are deburred. Compatible with all S and M models (not for 2021 models) S300 [WR130E], M500 [WR141E], M700 [WR142E], M1000 [WR143E], S450i [WR101 SI], S4. 50i [WR102SI], S450i [WR106SI], S700i [WR101 SI], M800i [WR111MI], M800i [WG757E], M900 [WG758E], M1000i [WG796E.1], M50. 0 2.0. [WR165E], M700 2.0 [WR167E]