These are called a "ten weight" or a "ten count" weight because it takes approximately ten of them to make up one pound of lead.  These can be used for a variety of applications but are often used on the bottom cord on throw or cast nets. 
This mold has a  1/4 inch pull pin.  
The overall dimension of the weight is 3in long by 0.41in in diameter.  
This mold is has four cavities.

Some people using a heavier lead line like this slightly fatter net weight sinker with its 1/4 inch diameter pull pin.  In order to keep the weight the same with the larger pin it had to be made slightly fatter.  

Some tips for this mold:

• The larger pull pin acts as a heat sink. 
• It may be necessary preheat the mold and pins.
• You may need to run your lead at a higher temperature.
• Use a light dusting of talc to break the surface tension to allow the lead to flow better.  
• By doing these things in test we were able to get four out of four good castings each time.