These snap electrodes provide the same signal transmission as the reusable electrodes, with added convenience and hygiene. Each peel-and-stick electrode is pre-gelled and designed for one use only. Use disposable snap electrodes with the LEAD110 series electrode leads. For best performance, use the LEAD110S-R and LEAD110S-W shielded leads for your recording electrodes and the LEAD110 unshielded lead for your ground or reference electrodes. Most appropriate for long-term biopotential measurement recording sessions, these pre-gelled electrodes have a circular contact area of 1cm diameter on a 41mm diameter backing that resists moisture. The electrodes include an adhesive solid gel that adheres well to the skin but leaves no residue when removed. Quantity: 50. (Available at a discount in quantities of 500. See EL502-10.) EL502 Long-term Recording Electrodes (Pkg. 50) EL502$35.00 Same Day Shipping - orders with UPS Red or Blue shipping will be shipped the same day if received by 3 p.m. PT (Monday-Friday).