Here's what MSR says. "The Heat Exchanger increases the efficiency of your stoves up to 25%. The unique waffled design channels the heat from the stove up the sides of the pot to increase the heated surface area. When used with liquid fuel stoves, or remote-burner canister stoves like the MSR WindPro™ II, it can also act as a wind block because it extends below the pot."

Retails for $80. Sell for $20 to a good home.

I'll be at the Midwest Mountaineering Expo in Saturday morning to mid-afternoon if you want to pickup.

Otherwise shipping $15. I just posted a bunch of stuff, if you want a few things I'll drop the shipping (I only want to break even).