Olfa Circle Cutter - from 1cm up to 15cm Diameter - Adjustable Rotary Circle Cutter - Comes with 5 Extra Blades - Ideal for Paper, Vinyl, Thin Fabrics, and Leather, CMP-1 :
Olfa Compass Cutter for cutting circles : Amazon.co.uk: Home & Kitchen
Olfa CMP-1 Compass Cutter | 50,000+ Art Supplies | Your Art Superstore