Hi
@MindyC , I'm in Canada so got my calipers at Canadian Tire, but I know many people get theirs at Harbour Freight. There's a sticky or page on using calipers that also has photos, I'll try to find the link after and post it...my eyes are similarly challenged lol. I also use a magnifying visor with a light, and a tiny light box as well...they all help me with drawing up doses. Actually, I didn't know how inaccurate I was eyeballing the doses until I got calipers, and I always double-checked/compared with my dh (the in-between units especially (like 0.25U) . And I never realized how poorly marked many syringes are, which leads to inaccurate dosing (calipers take the inaccuracy out of the picture). I *really* love calipers!
You can post on the main health forum to see what calipers others are using and where they bought them (they're not expensive), there's plenty of caliper users here

HTH, with love, Nikki
ETA: here's the link to the caliper page:
http://www.felinediabetes.com/FDMB/threads/dosing-with-calipers-updated-w-videos.79851/