Signum Pro · Polyester
Signum Pro Tornado
Heptagonal (7-sided) co-polyester with an axial twist, extruded, cooled, then reheated and twisted
Performance ratings
Lab test data
- Stiffness
- 215.5 lbs/in
- Tension loss
- 47.7%
- Spin potential
- 5.1
Overview
Signum Pro Tornado is a seven-sided co-poly with an axial twist, made by extruding a straight string, cooling it, then reheating and twisting it. Signum says the rough surface gives maximum bite on the ball and recommends stringing about 10% lower. Tennis Warehouse customers describe it as stiff and less arm-friendly. The TWU lab measured moderate-to-high stiffness and a fairly high tension loss, so expect it to need regular restrings.
Best for
- Spin-oriented advanced juniors
- Players who like a textured, grippy string
- Heavy topspin baseliners
Not ideal for
- Juniors with arm sensitivity
- Beginners and intermediate players
- Families on a tight budget
Pros
- Strong bite and spin from the twisted shape
- Good control
- Three gauges including 18
Cons
- Stiff and not arm-friendly
- Higher tension loss than the marketing suggests
- Premium price for a poly
Stringer notes
Twisted shaped poly: avoid kinks. Signum recommends about 10% lower tension than usual.
Break-in period
Short.
When to replace
Every 8-12 hours of play, or when it feels loose and dead.
Hybrid setup ideas
- Tornado mains with a softer poly or multifilament cross
Specifications
- Type
- Polyester
- Construction
- Heptagonal (7-sided) co-polyester with an axial twist, extruded, cooled, then reheated and twisted
- Gauges
- 16, 17, 18
- Colors
- Black
- Set price
- $15–$15
- Reel price
- $160–$160
- Brand
- Signum Pro (Germany)
Prices outside the US
The prices on this page are US retail in USD. We have not checked UK or Australian prices for this string yet, so we do not list them. Check a local retailer: gauges and colours can differ by country.
Sources & reviews
Data verified October 2026. Something wrong? Send a correction.
- Specs: Tennis Warehouse
- Pricing: Tennis Warehouse
- Lab data: TWU String Performance Database