Guy test tons of things. Test for hot and cold temperature retention and durability.
Good review, thanks for posting.
We’ve been happy with our Hydro Flask bottles. They have a few small dents but the lids are very durable and leak proof. They keep things cold on a hot day and hot on a cold day. We don’t use HDPE (high-density polyethylene) bottles much any more. About the only time is when we’re bicycle riding because the stainless bottles don’t fit well in bike frame bottle holders.