The Inventor Series

Built by the person who invented the game

Jeff Knurek invented roundnet in 1989, under the name “Spike-ball.” Thirty-five years later he is on our team, designing the equipment he always wanted the sport to have. Every product in the Inventor Series comes from his bench.

SHOP THE SERIES MEET JEFF
Two products. One standard.

THE INVENTOR SERIES

The Inventor Series exists to standardize competitive roundnet. Each piece solves a problem Jeff has watched players work around since the first prototype: nets that play differently court to court, and serve practice that turns into ball collecting.

Serving Caddy
Inventor Series

Serving Caddy

$54.95

Practice serves instead of chasing them. The pop-up caddy sits behind the net, catches what you hit, and rolls the balls back to you.

Catches your serves and rolls the balls back to you
Pops up in seconds, folds flat for tournaments
Doubles as a shade tent
See full product details
Net Tension Pro
Inventor Series

Net Tension Pro

$24.95
Official Equipment of the 2026 Roundnet World Championships

Tension is the one variable nobody could measure. Net Tension Pro gives you a repeatable number, so a rally bounces the same in pool play, on the show court, and at Tuesday practice.

Check tension in seconds — no tools, no calibration
Works with any set using standard netting
Match every net on the field to the same reading
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WHAT THE INVENTOR SERIES MEANS

Three rules Jeff set for the line before anything went into production.

Standardize the sport

If two teams meet in a final, the net should play exactly the same for both of them. Fair play starts with equipment you can measure.

Make training count

Reps beat sessions. Every training product is judged on one thing: how many quality touches it gets you per hour.

Designed at the source

Jeff designs, we build, tournament players test it. Nothing carries the Inventor Series mark until it holds up on a competition field.

Jeff Knurek
Jeff Knurek
Inventor of roundnet, 1989 · Product designer, Premier Spike
At his home office, 1992.
The inventor, back at the bench

Thirty-five years later, he is on the team

Jeff Knurek was a professional toy inventor in 1989 when he designed a game played around a small circular net and called it Spike-ball. The sport grew into a global one. Neither Jeff nor Premier Spike is affiliated with the Spikeball™ brand as it exists today.

He never stopped designing. By the time Premier Spike started showing up on tournament fields in 2023, Jeff was drawing his own premium set and a line of training accessories. When he found us, he saw that the durable, competition-grade net he had been sketching already existed. So he set the drawings down and sent a message instead.

Today Jeff is part of Premier Spike, and the Inventor Series is what came out of that first conversation. The Net Tension Pro makes fair play measurable across every tournament net. The Serving Caddy turns a practice hour into hundreds of reps. Both started as problems he had been thinking about for decades and could finally build.

The person who started this sport should get to help shape where it goes next.

Having Jeff on the team matters to us. Giving him a real hand in the sport he created matters more. Everything he designs from here carries the Inventor Series mark, and every set of it goes out with his name on the work.

From the archive

Photos from Jeff’s own files — the first prototype, the original box, and the years in between.

The original build, labeled by hand: “Spike Ball — indoor/outdoor game.”
The prototype
The original build, labeled by hand: “Spike Ball — indoor/outdoor game.”
The Tomy Games retail box that put Jeff’s design on shelves.
1989
The Tomy Games retail box that put Jeff’s design on shelves.
Jeff at the IDEA office, drafting table and Spike-Ball box on hand.
1990
Jeff at the IDEA office, drafting table and Spike-Ball box on hand.
The 1st Annual Roundnet Inventor’s Cup, Fishers, Indiana.
2018
The 1st Annual Roundnet Inventor’s Cup, Fishers, Indiana.

PLAY ON THE GEAR HE DESIGNED

The Inventor Series ships from our shop with the same 60-day warranty as every Premier Spike set. Club and tournament pricing is available on both products.

SHOP THE SERIESGET CLUB PRICING