Benchmark™ Overhead Stirrers

Category Overhead Stirrers
Manufacturer Benchmark Scientific
Country of manufacture China

Benchmark’s Overhead Stirrers feature high torque and advanced digital microprocessor control for smooth mixing of low and medium viscosity samples. Speed and run time are accurately set and monitored on the LCD screen. Both the 20L and 40L capacity models are supplied with a 4 arm stainless steel propeller. Additional steel and Teflon impellers are available. A feed-through chuck holds accessory shafts firmly in place and is easily tightened and loosened without tools. The overhead stirrers are protected from damage by sensors that shut down operation in the case of high viscosity or obstruction, while a splash cover protects the connection mechanism from potential corrosion. Unlike most mixers, the Benchmark series is also supplied with a support stand and mounting hardware. The stirrer easily and securely attaches to the stand for compatibility with a variety of vessels, up to 24 inches high.


  • LCD control panel
  • All-inclusive! Includes complete stand assembly and 4-arm stainless steel propeller
  • Compact and quiet
  • Digital accuracy and convenience
Key Attributes
Maximum volume (L): OS 20L: 20 L (water)
OS 40L: 40 L (water)
Minimum Volume (L): N/A
Speed max (rpm): OS 20L: 2200 rpm
OS 40L: 2200 rpm
Speed min (rpm): OS 20L: 30 rpm
OS 40L: 30 rpm
Max temperature (◦C): N/A
Plate:  N/A
Plate material: N/A
Torque max (Ncm): OS 20L: 40
OS 40L: 60
Controls: Digital
Timer: Yes
Programmable: No
Reverse rotation: No
Warranty (years): 2
Weight (lbs): OS 20L: 5.7 lbs
OS 40L: 6.2 lbs
Manufacturer Specifications
Model: OS-20L / OS-40L
Mixing Capacity (H20): 20L / 40L
Maximum Torque: 40Ncm / 60Ncm
Input Power: 60W / 120W
Output Power: 50W / 100W
Net Weight (Mixer): 2.6kg / 2.8kg
Maximum Viscosity: 10000mPas / 50000mPas
Speed Range: 30-2200 rpm
Motor Type: DC brushless motor
Chuck Diameter Range: 0.5-10mm
Exterior Dims.: (WxDxH) 7.3 x 3.3 x 8.7 in. / 18.6 x 8.3 x 22.0 cm.
Protection Mode: IP42
Ambient Operating Range: 5-40°C
Electrical: 100-240AC 50-60Hz
Warranty: 2 years

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Benchmark™ Overhead Stirrers Accessories