The CookTek ThermaCube FlashPak utilises a unique system, which enables the FlashPak to naturally convect warm air while situated at the bottom of the ThermaCube Bag. Suited to large ThermaCube bags, this unit is specifically crafted to retain heat for extended periods of time. Able to be re-used in subsequent replacement bags, this unit is long-lasting, durable and provides great quality for money.