The Derwent blender pencil is a soft colourless pencil that allows you to blend two or more colours together to create a new colour.
It physically mixes and smoothes the colours so individual strokes and hard edges are softened. Allows artists to blend away pencil lines. Effective with both colour and graphite pencils
The derwent burnisher is a hard colourless pencil which when used over layers of pigment provides a rich polished finish. Used over colour creates a burnish (Or shine) without changing the colour of your artwork.