This is an updated version of my original design, with an even slimmer sloped indicator base, for an even better parallax-free experience. Using a matte filament is recommended (Orange has the best contrast with the TSO blue).

One of the most common complaints about the Gen 1 TSO Parallel Guide system is that the metal cursor makes accurate setting of the cursor very diffucult. This aims to resolve this issue by providing a sloped cursor that makes contact with the ruler to negate the parallax as much as possible.