I think the label describes two diatoms, Diploneis chersonensis, and Diploneis didyma from Poole [Dorset, UK]. Prepared by RI Firth. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.40 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 15 images stacked in Zerene (Pmax).