I bought the wrong blades for my small rotary cutter last week.  How did I not know that there were four sizes, not three?
What size rotary cutter is best for quilting? - The Crafty Quilter
About OLFA –
OLFA Deluxe Rotary Cutter - 60mm - WAWAK Sewing Supplies
Ideal blade for medium to heavy-duty projects Circular rotary replacement blade for our popular 45mm rotary cutters used for quilting, sewing, and general crafts. Cuts up to 6 layers of fabric. This blade is made of high quality tungsten carbide tool steel for unparalleled sharpness and superior edge retention. For Original 45mm Rotary Cutter (RTY-2/G) and Deluxe 45mm Rotary Cutter (RTY-2/DX). 10 blades per pack.
Olfa 45mm Rotary Blade 10 Pack
Best 45mm Rotary Blades for Quilting –
Rigid Rotary Cutters – Woods Equipment
The Quilters Select 45mm rotary cutter has a weighted, ergonomic grip that will make cutting fabrics easier than ever. On sale at Moore's Sewing now!
Quilters Select Rotary Cutter 45mm- an essential tool for any quilter
IronCraft Rotary Cutter 1500 Series ROUNDBACK CUTTER - Chenango Supply Company
Stories Of Rotary Cutters
The Best Rotary Cutter for All Your Fabric-Cutting Needs - Suzy Quilts