Ive been drilling and installing these overflows in aquariums for over 15 yrs. There a numerous benefits to overflow boxes, to many to mention (google it). I built this one out of smoked acrylic so you can see what it looks like inside and outside. I will build and install these at my shop in Rogers, MN for anyone locally if you drop your tank off for a week (impossible to do onsite requires draining). The cost is as follows: $25 to drill hole $7 bulkhead $68 for fabricating overflow and installing with premium grade silicone this leaves a grand total of $100. You have your choice of 1.0 or 1.5 bulkhead with corresponding hole size. [1]