Hi - this is an outdoor electrical cable connector - use it to permanently encapsulate a cable splice into a solid block of resin to protect the joint from the elements. Commercial versions of these are used in industry for underground cables. This one is free and customizable! Its good for low voltage - pool, garden lights, boats, underground sprinkler wiring etc - the original version I made about a year ago has been underwater for over 12 months with no signs of resin degradation or water ingress yet IMPORTANT: THIS IS FOR LOW VOLTAGE APPLICATIONS ONLY It's not safe for connecting domestic 115VAC or 240VAC supply - don't even think about it! (use at own risk etc) Read more in the instructions tab for how to assemble and use.You need: a) polyurethane or epoxy resin + catalyst (available from any hardware or boat shop) b) tape for both ends c) tools to solder or join the wires Step 1 - customize and print out the size of connector shell you need - no support is needed to print - the funny little shapes are spacers to help locate the cable join right in the middle of the shell Step 2 - thread the cable through the joiner shell and out the top - splice the wires together by soldering or crimping. Consider putting heatshrink or tape over any exposed joins for added protection. Step 3 - fit the wires back into the shell - its extremely important to make sure the wires are not touching the sides and have sufficient space for the resin to fully encapsulate them. Use the little spacer things or small cable ties to hold the cable in place down the middle of the shell for the next steps (the spacers are designed to hang from the top of the shell) Step 4 - tape both ends - use tape that will stretch and form a tight 100% seal around the cable you're about to join so no resin will get out during the pour. Step 5 - follow the manufacturers directions to mix and pour resin into the shell - go slow and make sure there are no pockets or air bubbles. The resin needs to go right into the ends and all around around the cables where they enter the connector shell, then fill the shell right up to the top. Use a pin or piece of wire to work the resin into every nook and cranny. Step 6 - Clean up - cut off the ends from any spacers that are poking out from the top of the shell through the resin - that's it - you're done!