This is one of the earliest models of an Esterbrook Dip-Less well. These featured a self contained glass inkwell and could be found in numerous configurations, with chains, as doubles, various colors, etc. One of my favorite style dip-less.
This is the most basic of all the dip-less desk sets, in fact not even pictured in most catalogs. Offered in black only.
One of the most popular dip-less sets Esterbrook made. These were often found in banks, post offices and anywhere where a large supply of ink was needed for the general public. Also available with a chain for such purposes.
431 Elevator Dip-Less
This was a short lived dip-less set called the "Elevator"
431 Elevator in Maroon
Here's the same Elevator in Maroon. Hard to find in colors other than black. This one with a clear red tailed dip-less pen.
Sometimes referred to as the "Hockey Puck" because of its resemblance, the 444 was a very popular style of dip-less set which came in a multitude of colors, in doubles, in deluxe configurations and with a chain for public use as well.
444 Later Style
Esterbrook changed the style of the 444 at some point to this more futuristic design, this one in green. Note the colors of these refer to the glass base itself, and not the actual top. The top was always black.