UY Wire Connector: Product information:
Used to connect two wires safely and rapidly with moistureproof.
Applied to the conductors with inner diameter of 0.4—0.7mm.
The most insulated external diameter is 1.52mm.  
Product information:
Moistureproof, and used to connect two wires safely and rapidly with two pins.
Applied to the conductors with inner diameter of 0.4—0.9mm.
The most insulated external diameter is 2.08mm.