Replacement parts for all those consumables within the T-Rex. Choose from a complete set of o-rings (6 pack), stylus and cylinder o-rings only (4 pack), or stylus o-rings only (3 pack). You’ll need the stylus o-rings more frequently, and once in a while you’ll need to change out the others inside the tool. To make your o-rings last longer, apply o-ring grease frequently.