What is a Leadholder?
Leadholder can be broadly defined as any durable instrument that is designed to hold and be refillable with consumable pieces of graphite so that the graphite can be conveniently used for drawing or writing. Within this definition there are subsets such as porte-crayons, mechanical pencils, and drafting leadholders. This website is primarily concerned with drafting leadholders, which are commonly called by draftsmen in the US as simply leadholders.
... Because leadholders of this type are the specialized tools of draftsmen and artists, they are generally unknown to those outside this coterie. You can probably find one or two models at your local art supply store if you look hard enough. Not long ago you would have been confronted with dozens of makes and styles of these instruments.
... The history of thick lead leadholders, I think, is nearly closed. In the 1950s there were hundreds of varieties, many of superior quality and with unique features. Now there are few manufacturers still producing them, and even fewer, I'm sure, with any desire to improve them.
but this's what i use the kooh-i-noor 5649.