The Ultralites are made from HDPE plastic, which has a very long and safe track record. But it’s not that different from the Tritan version in weight. The Ultralite comes in at 72g with the lid and the Tritan (with lid) comes in at 90g. Capacity is different though. The Tritan’s measurement lines stop at 14oz and the Ultralite stops at 16oz with a couple of oz to spare.

The plastic is a bit softer. It’s fine for dishwashing but near-boiling water will start to soften the plastic and enough pressure can start to warp the shape slightly. HDPE also has a slight smell and tends to hold flavored drinks a bit. Tritan seems to be better on all of the above.

But still, great little bottles at a nice price. I use Tritan for sports drinks and the HDPE if I need to carry water and want to cut every gram of weight.