Chug lids for PRO 17, 21 and 32 oz bottles are interchangeable. Chug lids from PRO Steel are not interchangeable with 24oz plastic PRO Lite bottles.
Straw lids are not interchangeable at all due to the straw length.
The new FLIP lid (which is the ONLY lid that can be used on our stainless steel PRO bottles with HOT liquids) is compatible with 17, 21 and 32oz stainless steel PRO bottles.