There are type 1, 2, 3 SPD,

Type 1 SPD protects from the directly lightning strike to your power supply line.
Type 2 SPD protects from indirectly lightning strike, this type of SPD is the one you install at your DB, it has less discharge current rating
Type 3 SPD protects sensitive equipment such as computer, AV equipments or electronic devices, type 3 SPD must install nearby your electronic devices.

In Malaysia, you will need type 3 SPD, if you stay at high ground or frequently lightning strike area, you will need type 2 SPD, if the power line is hanging in the air and connect to your house and your house is at the highest point, you better get type 1 SPD.