The Spidertrax High Performance Outboard Oil Seal Kit provides an easy and clean solution for installing seals on the outboard side of your Spider 9 housing (wheel side). Each kit comes complete with steel seal housing and two rubber seal inserts. Steel seal housing is designed to be welded in place. For detailed installation instructions, CLICK HERE. This outboard seal was designed specifically with rear ends in mind. It provides a great solution for increasing the amount of housing oil you can hold, which is becoming more common place in Ultra4 racing. Simply weld this outboard seal on the wheel side of your Spider 9 housing tube, and the housing tubes themselves can now serve as an area for increased oil capacity. In this case, you would run this outboard seal design over our aluminium inboard aluminium seal design (the one that seals near the diff). The choice is yours, both have their advantages. For front housings (steering axles), this outboard seal can serve as a great way of keeping dirt and debris out of your Spider 9 housing tubes. In this case, wed still recommend running our inboard aluminium seal design (seals near diff). Seals are designed to accommodate all Spidertrax Ultimate Axle Shafts up to 40 splined diameter.