Hi, I think you are right.... the number maybe a land line. Anyway, I emailed him through his GR-research.com website. Danny confirmed with me he was the one that designed the upgrade skiing ninja crossover for this speaker. The problem is Danny stated that he can sell me the kit's COMPONENTS (bunch of capacitors, resistors....), and I will have assemble them myself!!. While I can solder here and there a little... I dont have the knowledge, experiences, and capable to assemble the complete circuit board from scratch. Even my local tv repair shop refuse to do this job (liability, I guest).... They are happy to replace few components here and there. I preferred to buy a completed/finished build crossover. I know it is far fetch... but does anybody by chance have a skiing ninja crossover for the Onix Rocket RS750 for sale?? I will also post this question on the other sections....