Deep well concave slides are ideal for observing live aquatic specimens. Deep well slides can hold more liquid, minimize the effects of evaporation on live specimens Double concave microscope slides. Deeper well: well depth 2-2.6 mm. Well diameter: 20 mm. Standard slides size: 1"x3" (25.4x76.2mm). Thicker slides: 4.8 - 5 mm thick. Clear glass. Ground edges. One slide.