Ferris SRS Z1 Series 36" Mower Stand On Vanguard 627cc Engine (5901941)Ferris SRS Z1 Series 36" Mower Stand On Vanguard 627cc Engine (5901941) The SRS Z1 offers all of the same great productivity and comfort as the larger SRS Z2, but in a more compact package. With smaller mowing deck options, the Z1 is optimal for navigating through tight gates or loading on smaller trailers. True to the Soft Ride Stand on (SRS) series, the adjustable operator platform on the Z1, features suspension technology, offering operator comfort