Boekel Scientific has a full line of laboratory jacks for all of your experiment needs. These all-metal scissor jacks are used to hold flasks, heaters, or bottles in place. All stainless-steel screw mechanism and anodized aluminum top and bottom plates. Three sizes have a pre-tapped hole to accommodate an optional support rod. The Giant size, 19090-005B has a side locking knob for the platform.