You did not specify the maximum current required. The PP30 is 30 Amps, the PP45 is for up to 45 Amps, and the SB50 good for 50Amps with a more robust connector and housing. Each version is sized for the appropriate gage wire for the amperage. For all my electronic work I use mostly PP30. The same $45. Crimp tool will do PP15, PP30, and PP45 powerpoles. Note: the PP15, 30, and 45 are all capable of interconnecting. The crimp tool is the only way to go in my opinion. You can solder the connector pins to the wire if you are very good and do not get excessive solder on the connection, which hinders or prevents pushing the pins up into the plastic housing.