Instead of spring, the mouse head block tether uses a fine .010" diameter looped wire, making it extremely light weight and allowing it to transmit torque efficiently to the swivel as the mouse moves. A small peg attaches to the animal's skull with dental cement. The wire tether is attached by inserting it into a hole in the peg and sliding a sleeve over it.
The tether includes a special slotted clamp (replacement part MCLAMP) for direct attachment to the outlet tube of our our low-torque single or dual channel swivels (models 375/25 or 375/D/22QM). Always use with an SMCLA counter-balanced lever arm.