It's not surprising that Serena Williams is endorsing the new Blade SW104 Autograph Countervail since it's a racquet whose power can be dangerous in the hands of someone who has the strength and technique to wield it. Don't be fooled by the modest 11.4 oz static weight, this racquet is definitely no lightweight. Because of its extended length (28 inches!), the Blade SW104 Autograph Countervail swings heavier than the Pro Staff RF 97 Autograph and the legendary 6.0 85. The payoff, according to our playtest crew, is stability, plow through and power. Put simply, this racquet crushed the ball, and it didn't get pushed around when trading heavy balls. The downside is that a 28-inch racquet with a 341 RDC swingweight isn't so easy to maneuver, especially on reaction volleys and body serves. Indeed, this beast of a racquet is unkind to lazy feet and slow preparation. There were also some complaints about the control, which is understandable given how much power this stick has when fully deployed. Ultimately, the Blade SW104 Autograph Countervail was like a double edged sword. It wasn't the easiest weapon to wield, but when the stars aligned and our preparation was on point, the results were outstanding.