I use the sections cut from a single plastic rod tube, there smaller than the commercial bought ones and then either slide old carbon through to make them inline or use wire from a model shop to mak them elasticated.

Weight wise I can tailor how heavy by making them with 1 – 2 or 3 24mm lead discs which are then areal dieted in, it’s a fiddly process but I make generally 25-30 in one session and there done in no time, cast excellent and in my opinion far better than the commercial version.

i just use bottle tops ( and there are a variety of sizes available) some stiff polythene tubing, lead sheet for roofing and araldite rapid for my inline banjo feeders. they are not as professional as the preston banjos but they work.
if you get a slightly deeper bottle top then affix your lead inside the top otherwise bevel the edge of the lead disc and araldite to the underside.
if the bottle tops are the wrong colour a quick painting will help match the bottom colours of the lakes etc you fish.
give it a go, you will enjoy it. 🙂 🙂
ps dont forget to warm the ends of the poly. tubing to prevent cutting into your line.

I made some out of 2ltr milk bottle tops, discs of roofing lead and old no 1 section , they look rubbish so I’m going to sell them on EBay.