Use needle electrodes for stimulation or recording in animal subjects and tissue preparations. These non-ferrous, 28-gauge stainless steel, needle electrodes are equipped with a flexible lead terminating in standard Touchproof connectors. Use one EL451 electrode, plus one EL452 ground electrode, when recording from a single site (e.g. studies of individual muscle fibers). Use a pair of EL450 or EL452 electrodes, plus one EL452 ground electrode, for general-purpose recording (e.g. ECG). For stimulation, use a pair of EL450 or EL452 electrodes. Teflon® coated needle electrodes are fully insulated, with a clear Teflon® overcoat, except for the conductive needle tip. Needle electrodes are shipped non-sterile, so pre-sterilization is required.