Dunlop Black Widow 18

Dunlop Black Widow is one of the softer polyester strings around, hence it is easier on the arm.  The 7-sided star shape produces tremendous spin.  Great for the player looking for low powered string, Black Widow allows great control with high swing speeds.
"This would be a great "starter poly" if you have never tried them before. Furthermore, anyone who has used polyesters for a while and is just looking for a softer, crisper feel should definitely give Black Widow a try!" -- taken from Tennis-Warehouse.