​Crosses: Pro's Pro Black Out is an innovative high-tech co-polyester string with pentagonal cross-section.
Black Out's unique profile provides crucial extra spin and control. This string does not slip or lose tension and provides excellent performance. In addition, Black Out is extremely durable and designed for demanding tournament players.

​Pro's Pro B-400

Pro's Pro B-400 is a highly durable all round string constructed from a multifilament nylon co-polymer core, which is wrapped with braided filaments. It offers a combination of good elasticity, high durability and persuasive power.

​Pro's Pro Dura Ace

Pro's Pro Dura Ace​ is a high performance squash string for demanding players, providing excellent control, efficient power and excellent durability.
The multifilament string core of high quality micro fibre is wrapped with 2 layers of woven micro fibres

Very good question?
I take three powerangle centric rackets on court, Why, Ok here goes.
One racket is strung at 50 Ibs  (my powerangle rackets max tension is 53Ibs but because I am using poly string I take off 5%) This racket I use when the balls are new and "flying" (I need the control!)
My middle racket is strung at 48Ibs this racket I use when the balls have settled down and are easier to control, but I still want the same power I had earlier.
The third racket is strung at 47Ibs for when the balls have gone off or are damp / wet, I still have the depth of shot with the same swing as normal :-)

I will change the rackets to the conditions: Example If I am serving into the wind I will use the third racket (more power to punch through ) same effort from me!

Serving / playing down wind I use the first tight strung racket for control.

A bit like using winter tyres on snow / ice or summer tyres in the dry conditions!
With three rackets at different tensions you have the choice to adapt to the conditions.

Hope this helps!
daveg