The amino silane surface on UltraGAPS™ slides is ideal for printing long (>50 mer) oligonucleotides. UltraGAPS™ slides have a more hydrophobic surface than competitor slides, resulting in smaller spots. A quality certificate is included in each box of slides. Each lot is tested for consistent spot morphology, signal intensity, and low background in a hybridization assay. The results of nine quality parameters are listed, including DNA retention and an image of the spot morphology for that lot of slides. Each case of UltraGAPS™ slides includes optimized protocols for use and troubleshooting hints.