I’ve been using a 100 pound sandbag for a long time decided to go for the 150. Build quality seems very good. Bag is made of a 1000 denier style material like luggage. Has a number #10 YKK self healing zipper underneath a heavy Velcro flap. Inside that zipper is another bag with a Velcro closure, you unroll that inner bag to fill. So far about a month of pretty heavy use no leakage, no tears no issues. The bag seems to have stretched slightly and I may top it up. My only complaint so far is filling it was a little annoying. Specifically the mouth of the inner bag is relatively small. Part of the problem also might be that I filled it with playground sand which was 150 pounds nominally, but was slightly wet and therefore clumpy. All which is to say it didn’t pour smoothly, making the process more arduous than I expected. My other nit is that the 150 pound bag seems to have room for exactly 150 pounds of sand. Not a teaspoon more. Which again made the process of filling it annoying. After adding the first 2 50# bags of sand, I thought there’s no chance of third bag is going in here. It did, but again very tight margins and towards the end, I was scooping trowel fulls in, shaking the bag down, and then adding another trowel, full. What that says to me is, if you chose to fill it with something like pea gravel or driveway gravel you’re not gonna get 150 pounds in there. I would probably avoid gravel anyway because I think it would cause the bag to wear faster due to its edges. Anyway very happy with the product so far. I just ordered the 200 pound bag. Cheers.