Different qualtiy rosin cakes have different influences on sound colour and bowing techniques.  Violinists and violists need a more dry or hard rosin, cellists a medium and double bassists a more sticky rosin.  Steel strings can be better palyed with dry or harder rosin, synethetic strings with medium and generally gut or gut wound strings with a more sticky rosin.  Dry rosin is best in tropic climates and soft rosin in cold climates.  Which ever rosin you choose don't forget to clean rosin away from the strings and body of your instrument using a soft, dry cloth such as the Microfibre cloth ($7.95).

Violin/Viola Rosin	Cello Rosin	Double Bass Rosin