Langstroth medium plastic frame made of food grade plastic.  

Due to narrowed top and bottom bars, there are 10 % more cells in the medium plastic frames than in comparable wooden frames. There will be more space for honey. in addition, the plastic frames withstand extracting of thixotropic (heather) types of honey excellently.

For a short time, polypropylene frames can withstand heat up to 115 ºC (239 ºF), so that they can be treated by steam with a pinch of salt. The new frames tolerate steaming well, but the frames can lose their form in a long run. This is caused by the absorption of wax into polypropylene. In addition, during a longer period, the frames can bend or curve. Modern Beekeeping is not liable for the damages caused to the frames.

The frames can be cleaned using a metal spatula to separate the honeycombs apart from the frames and steaming them. After that, the frames will be washed by a steam pressure cleaner and reused. The polypropylene frames can also be retted in cold water with caustic soda overnight. After that, the frames will be cleaned with water and a dishwashing brush. Or the frames can be cleaned only scraping the comb with a spatula and after that reused again.