Nuvo Aqua Shimmer Pens are uniquely designed to create a glitter effect to images and media.The perfectly formed brush nib makes these pens extremely versatile and is perfect for adding small glittery detail or making large shimmering areas. Can be used with Aqua shimmer pens to creat vivd watercolour images with a hint of glamour. Each pen has it's own reservoir complete with a non drip valve. Apple different amounts of pressure to the reservoir to control the amount of liquid released.