Wire Ferrule Kits: The 1640-piece crimp terminal connector set includes 590 pre-insulated wire ferrules and 1050 uninsulated crimp terminals. Interface type: AC/DC. Working frequency: low frequency. Uninsulated Butt Connectors: 5 types uninsulated electrical terminals: 0.5 mm (400 pieces), 1.00 mm (200 pieces), 1.5 mm (200 pieces), 2.5 mm (150 pieces), 8 mm length. 4.00mm (100pcs), 9mm length. Pre-Insulated Terminals: Insulated wire ferrules with PVC heads in 5 types: red 0.5mm (200pcs), blue 1.00mm (150pcs), black 1.5mm (100pcs), yellow 2.5mm (80pcs), green 4.00mm (60pcs). Application: The non-insulated crimp ferrules can effectively prevent the wire ends from being stripped or broken. The copper wiring ferrules have good electrical and thermal conductivity, which can provide reliable connections. These ferrules designed with insulation flare make wire insertion easier. Tinned Copper: The electrical butt connectors are made of red copper, tinned to prevent oxidation and rust, more durable to use. Widely used for electrical projects, workshops, automotive electricians, machinery, cars, trucks, motorcycles, etc. How to Use: Remove the wire core from the case. The stripping length should be as long as the metal sleeve of the terminal. Place the entire core inside the wire end ferrule terminal without being exposed, and then crimp the terminal. Before that, please adjust the crimping tool according to the thickness of the wire core.