The HabiStat Mesh Panels allow for added air flow and exchange throughout the Terrarium and provide greater control over humidity. Having a fully mesh enclosure can prove hard to maintain heat and humidity for certain species. A full glass enclosure, while great for temperatures, can be more difficult for humidity control, again, depending on the species you keep and their requirements. The mesh panels allow for this improved and important air-flow which in-turn allows for better humidity and even temperatures control.This kit contains two mesh panels which can be inserted in the side of the Terrarium in place of the small glass panels.Easy to install, these panels can be put in place during or after the Terrarium is set up.If adding after the Terrarium is set up, its simply a case of removing the 4 screws of the HabiStat Terrarium top and carefully lifting it off.Once removed, simply replace the small glass panels for the HabiStat Mesh Panels, then replace the top and resecure with the previously removed screws.Available in four different sizes.HabiStat Glass Terrarium 45cm (18'') high:- Fits HGT4545 - 45 x 45 x 45cm (18 x 18 x 18") HabiStat Glass Terrarium- Fits HGT6045 - 60 x 45 x 45cm (24 x 18 x 18") HabiStat Glass Terrarium HabiStat Glass Terrarium 45.7cm (18") high: - Fits HGT9145 - 91.4 x 45.7 x 45.7cm (36 x 18 x 18'') HabiStat Glass TerrariumHabiStat Glass Terrarium 60cm (24'') high:- Fits HGT4560 - 45 x 45 x 60cm (18 x 18 x 24") HabiStat Glass Terrarium- Fits HGT6060 - 60 x 45 x 60cm (24 x 18 x 24") HabiStat Glass Terrarium- Fits HGT9160 - 91.4 x 45.7 x 60cm (36 x 18 x 24") HabiStat Glass TerrariumHabiStat Glass Terrarium 90cm (36'') high:- Fits HGT6090 - 60 x 45 x 90cm (24 x 18 x 36") HabiStat Glass Terrarium- Fits HGT9190 - 91.4 x 45.7 x 90cm (36 x 18 x 36") HabiStat Glass Terrarium