Drain plugs have a tendency to walk off sometimes. Fortunately, replacement drain plugs are available from Bison Coolers. All drain plugs are available in 2-Packs so you can always have a spare. Bison Drain Plugs (GEN1) are direct replacements for GEN1 Coolers only. These were manufactured between 2012 and 2017. If your drain plugs don&';t look like these, then you should reference the GEN2 Bison Drain Plugs.