From unbelievably delicate lettering to extraordinarily intricate flowers, this bright, beautiful bundle of extra-fine pens excels at expressing the finest lines with expert precision on your Cricut cutting machine. Make memorable wedding invitations with glorious detail. Adorn greeting cards with surprisingly thin doodles and drawings. Use with Cricut Explore (Cricut Explore One requires Accessory Adapter) and Cricut Maker machines. Pens are water-based, acid-free, nontoxic, permanent after dry, and conform to ASTM D-4236.