I looked at the range of plug options available on Amazon and settled on these. The images you see on the product details page do not do justice to the quality of the packaging which is first class. This said, if you are an environmentalist you might think the packaging somewhat overkill! but it does compliment what turns out to be a very nice quality product.
The plugs come with no instructions for "assembly", but you will find the process painless. To access the core simply hold the sprung end gently between thumb and forefinger and with the barrel pointing away from you unscrew the insulating cover in the conventional way with the other hand (i.e. anti clockwise if you are looking along the barrel).
One word of caution - try not to undo the grub screws too far or you'll be hunting for them on the floor.
It took me about 20 mins to use 2 packs of these to terminate my bi-wire cables at my Mission speakers. A slight pre-squeeze on the sprung ends aided insertion into the speaker binding posts. Results? - brilliant as far as I'm concerned. Highly recommended.