Looking at these REAN jacks Official Speaker Repair Site - Orange County Speaker - Home of GLS Audio 1/4” PLASTIC REAN JACK 4 Pack They look like they are a bit more sturdy and easier to solder the speaker wires to them. A few questions here... 1) How are these better/worse/different from the standard TR jacks without the black plastic casing? 2) Which is + and which is - on these? Also, on the third image on the link, it shows 4 lead/contact points instead of just 2 --- how to use this? Thanks!