DSPIAE PT-SR Sprue Rack Model Making Tools

Great product, for a model kit you need 2 pack of these, its good and the sprue fits nicely

The DSPIAE (Which is meant to mean 'Display') Sprue Rack box is a set of 5 plastic pieces with a wedge hole and an extended tab that another sprue holder can click onto.
5, is in my opinion not enough, I recommend getting 2 packs, especially if you care about having multiple letters.

You get 1 white sprue with one of each alphabetical letter and one of each number on it, plus five extra 1's and 2's, as well as a 'PC' for PolyCap. Each holder has two slots for letters/numbers, so you can put in "A1" or "E5".
You also get a rubber sticker sheet for putting on rubber feet on the sprue holders - I'd suggest keeping it, since you can cut out more pieces for other things.

There are different versions of sprueholders out there, such as Gunprimer clips which are meant to stay on the sprue, there are racks that don't tip over but are often 'overcrowded' and then you have these, which are a bit of a mix.

They have a wedge hole and are not meant to clip onto sprues, you pull the sprue out every time and then slot it back in when you're done with it.
This works well when the holders are clipped together, but by themselves they're too light to hold up large sprues and either tip over or the sprue slips out sometimes.

You can separate the black from the red with a parts separator and add something like a weight or tungsten putty inside, then clip or glue them back together, to weigh them down even more.
Technically you could also store the letters inside, but I wouldn't really recommend it.

Overall, they work just fine, for the most part. They struggle with larger sprues or sprues with weird corners (you have to place the corner of a sprue, can't place it midway).
I was able to place Warhammer runners (sprues) into them as well, so it's not just the thin Bandai ones, though they might struggle a bit with the old kind of thick GW ones.