Hanna Heavy-Duty Magnetic Stirrer with Speedsafe

A magnetic stirrer drives a stir bar inside the vessel through the plate, so nothing enters the liquid and there is nothing to clean but the bar itself. This is the heavy-duty frame: 2.5 litres of stirring capacity, which covers beakers and flasks up to that volume with enough torque to keep a viscous solution moving rather than letting the bar slip.

Speedsafe

Speedsafe is the feature that separates a laboratory stirrer from a cheap one. If the stir bar decouples — which happens when speed is raised too fast, when the vessel is off-centre, or when viscosity changes as a solution mixes — the drive detects it and cuts back rather than spinning a dead magnet under a stationary bar. A decoupled bar that keeps being driven jumps, chips glass and splashes.

Two catalog numbers cover the range: HI300N-1 and HI310N-1, both 115 V.

For work that needs the direction to alternate, the auto-reverse model is the one to look at; for a timed protocol, the timer-controlled model at 5 litres. This frame is the general-purpose choice.