both are isp products, the 2 part 40 is more for tubing to flat surface. the 16 is thick and works wonders. google the product or find an acrylic store. shipping may hurt depending on where it comes from since its considered a hazardous material. if online the cheapest i found was $95 for 1 gallon. at the acrylic supply shop near my house i buy 2 for that price. the DIY calcium reactor thread was made with acrylic and 16
_________
just one little sps frag tank with lots of goodies |