Looks tough, feels tough, is tough! Gives a solid hand hold for two-handed casting. This item with a 0.375 (3/8") center hole weigh 20-22 grams before any reaming/drilling; those with a larger hole would weigh less. The Winn equivalent, while more comfortable to hold and nicer to look at, weighs only 7 grams. For most freshwater use, I think the best way to utilize this item is to balance the rod by adding extra weight behind the reel seat. I did this with a 6'3" rod a while back, and it worked great. One advantage of split grips is that the fighting butt can be added AFTER the rest of the components are attached, giving you several options to get the rod properly balanced. I've never tried squirting silicone caulking into the blank, but that would certainly add some weight.
Rated 5 stars for quality and usefulness. This is one of those items that should always be on hand if you build split grips.