These are blue insulated solderless ring terminals.
| Order# | Stud Size d2 | 
| 12-650-100 | #1/4, 6.4mm | 
Thickness .032"(0.8mm).
Sold in package of 100 pieces.
Other wire size are available.
| Order# | Stud Size d2 | 
| 12-610-100 | #4, 3.2mm | 
| 12-620-100 | #6, 3.7mm | 
| 12-630-100 | #8, 4.3mm | 
| 12-640-100 | #10, 5.3mm | 
| 12-650-100 | #1/4, 6.4mm | 
| 12-660-100 | #5/16, 8.4mm | 
| 12-670-100 | #3/8, 10.5mm | 
 
    
             
 
 
 
 
  
 