Buy Digital Drum Anyone Know Where I Can Oder/buy Just A Digital Drumset Kick Drum Pad?

Anyone know where I can oder/buy just a digital drumset kick drum pad? - buy digital drum

I just a used Simmons electronic drum SD5K and not on the drum pad. Does anyone know where I have to order or buy just the drum pad. And if I can find this book as a whole would be a different game? Thank you!