1.Adjustable speed range. 2.Rubber non-slip mat to prevent slipping 3.shaking plate can bear heavy load 4.Build-in timer is up to 999 hours, and alarm when time out 5.Long service time. SPECIFICATIONS: US-500D, US-505D ( DOUBLE PLATFORM) PANEL TYPE: Digital Display SHAKING TYPE: Orbital SHAKING SPEED: 30 to 250r.p.m. , 30 to 150 r.p.m. SHAKING STROKE: 25mm TIMER: 999 h/ m/ s POWER VOLTAGE: 110 V, 60 Hz / 220V, 50Hz PLATFORM DIMENSIONS( mm) : 330x280 OVERALL DIMENSIONS( mm) : 330x280x170 330x280x370 WEIGHT( Approx.) : 11, 12