Cat. GG-12-PDL: 12mm diameter, # 1 thickness, 90 pieces of CE certified crystal clear German glass coverslips with poly-D-lysine coating on both sides for cell culture and confocal fluorescence microscopy, sealed 15 pieces per bag x 6 = 90, sterilized, ready to use for your cell culture, can be used together with 24 well plates. Additional info: H-12-PDL is half size package of GG-12-PDL. They are identical items with shelf life of 1/2 year in -20C freezer.