$4 isn't bad but the one you linked to is 10?tangmonster said:I was lazy
So i have bought 2 of these boards
http://cgi.ebay.com/Speaker-Protection-Board-DIY-Power-Amplifier-/330521090172?pt=LH_DefaultDomain_0&hash=item4cf497987c
i got them for $4 each free shipping.
just browse around ebay.
Since they are so small , they get shipped in an envelope ,and isn't flagged by customs. Got both of mine within 3 weeks. depending on wattage you mights want to put in some better relays
The relays I am planning on using
"It contains a tungsten leading contact which can switch 100A (at 50V) loudspeaker current.
After closing, this contact is bridged by a gold plated silver contact, giving negligible contact resistance even at small currents (mA)."