VIVI Cap Multi Insulin Pen Cap For Use with Prefilled and Refillable Insulin Pens 2008-01-VIVFeatures Fits over insulin pen and adjusts constantly to keep the insulin pen at the higher end of room temp Keeps insulin protected from hot and cold temperatures Built in sensor features easy to read temperature assurance indicator Pocket sized design is convenient for travel Lasts for years and helps reduce insulin waste No need for maintenance, batteries or charging: Just Click n Go For use with multi model refillable insulin pens and pre filled