RIO'S Powerflex Plus Tippet is the strongest nylon tippet material ever made, with tensile strengths up to 20% more than regular tippet. A highly technical formulation of the nylon copolymer manufacturing process has resulted in this prodigious strength increase, without compromising knot strength or suppleness. Simply put, this is the strongest, most reliable tippet ever made.

Powerflex Plus is available in "regular" sized spools and in a useful, money-saving "3-pack" option (3 regular sized spools, conveniently packaged in a handy plastic tub):

The strongest nylon tippet material ever made