Armstrong's Hydroboard ceiling tile is for high humidity environments such as swimming pools, gyms, changing rooms and toilets as they're designed and manufactured to be 100% humidity resistant. These design features mean that Armstrong Hydroboard ceiling tiles are best installed into a corrosion-resistant grid too. 600mm by 600mm, this square edge ceiling tile is smooth in appearance and insulated for better thermal and acoustic performance from the suspended ceiling. Installing this lightweight ceiling tile in a grid system is extremely easy, and there are 40 in a box too to make larger projects even easier. Product Specifications Length: 600mmWidth: 600mmQuantity: 40Edge: Square