MC4 connectors are the must have things if you installing more than one panel. They keep the connections clean and tidy as well as easy to disconnect and reconnect. They are almost water resistant and you can use them to safely connect the panels outdoor. They have locking tabs to make sure that they keep connected well. 5 pairs at less than $15. They are a bargain at that price. Quality is topnotch.
5 Pairs of MC4 Male/ Female Solar Panel Cable Connectors
5 Pairs of MC4 compatible Male/Female Solar Panel cable Connectors (5 pcs of MC4 Male, and 5 pcs of MC4 Female).
Watch the below video on DIY MC4 wiring