OLO 4 piece set includes eight colored half-markers that twist together to form four markers. Traditional markers only have approximately 2ml of ink total. OLO’s patented free-flow ink technology uses over 90% of the ink compared to standard marker technology, with only 65-70% ink usage. Each OLO half-marker has 2ml of ink, more than a standard alcohol marker. Use an OLO Connector Ring (included) with any two half-markers to create a double-ended marker with over 4ml of ink! Combine half-markers to create unique double-ended markers that feature your choice of colors. Each half-marker is tipped with the OLO brush nib providing a smooth, fluid feel while maintaining balance and control. Colors included in this set: R1.5 Lingonberry, Y2.3 Buttercup, O2.4 Golden Poppy, G1.4 Spearmint, BG0.4 Turquoise, V2.4 Violet, B0.5 Blue Sapphire, and K Pure Black