Think about the electrical surge as an ocean wave, the Type 1/2 devices such as the SECO Surge Mitigator or Eaton Ultra will reduce the high intensity large wave but allow small ripples through unaffected, whereas a Type 3 point of use surge protector will soften the smaller ripples but have little effect on the larger waves (in fact it's likely to be damaged).
So you want a Type 1/2 device, and the Type 3 devices for full protection. These are only going to help with electrical line based spikes / surges coming into your house, so for some devices (router, cable) you may want to add coax or other protection.
|