Amazon.com: Universal ECG/EKG Electrodes Limb Clamp Reusable Nickel Banana Clip Din Clip Adapter Both 4.0 and 3.0mm Adult Size Set of 4PCS : Health & Household
Clips-Red ECG Adaptor Fits any 3 mm to 4 mm lead wire (set of 10).
Accessories | Vmed Technology
ECG Limb Clip - 3 Lead (Equal to Criticare CR-1166)