GF 218 WindowMark™ Blockout is an 8.0 Mil gloss white print media with dual-layer construction. GF 218 is designed to be 100% opaque and is excellent for window graphics & retail displays where total opacity and zero light transmission is required. GF 218 WindowMark™ Blockout is outdoor durable for up to three years and the clear removable adhesive is ideal for shorter-term promotions where clean removability is required.