CAUTION! The Post Office has been very late with delivery on most orders during the Covid 19 Crisis, so UPS (Standard Shpping) is the more reliable option!
Standard caulk-gun size tube (10.3 FL oz) of aquarium safe silicone sealant. Available in both clear and black. We've been using this brand for decades on our own aquariums and in the manufacture of our sponge filters.