QUANTIFOIL? with circular holes is mainly used in cryo-EM. The roundness of the holes is advantageous with respect to the formation of an ice layer of constant thickness.
R 1/4 
R 2/1 
R 3.5/1
The QUANTIFOIL? types with small holes (e.g. 1.2 μm) were designed for magnifications around and higher 50.000x. At magnifications between 30.000x and 40.000x we recommend the QUANTIFOIL? types with 2 μm holes. Larger holes (e.g. 3.5 μm, 5 μm) are suitable at magnification around 20.000x.
The table below gives an overview of the available QUANTIFOIL? types with circular holes. Please be aware that the hole size and spacing might vary slightly from their nominal value, whereas the period is fix.
| QUANTIFOIL? type | Hole size in μm | Spacing in μm | Period in μm |
| R 0.6/1 | 0.6 | 1.0 | 1.6 |
| R 1/1 | 1.0 | 1.0 | 2.0 |
| R 1/2 | 1.0 | 2.0 | 3.0 |
| R 1/4 | 1.0 | 4.0 | 5.0 |
| R 1.2/1.3 | 1.2 | 1.3 | 2.5 |
| R 1.2/20 | 1.2 | 20.0 | 21.2 |
| R 2/1 | 2.0 | 1.0 | 3.0 |
| R 2/2 | 2.0 | 2.0 | 4.0 |
| R 2/4 | 2.0 | 4.0 | 6.0 |
| R 3/3 | 3.0 | 3.0 | 6.0 |
| R 3/5 | 3.0 | 5.0 | 8.0 |
| R 3.5/1 | 3.5 | 1.0 | 4.5 |
| R 5/10 | 5.0 | 10.0 | 15.0 |
| R 5/20 | 5.0 | 20.0 | 25.0 |
| R 6/6.5 | 6.0 | 6.5 | 12.5 |
| R 6/100 | 6.0 | 100.0 | 106.0 |
| R 10/5 | 10.0 | 5.0 | 15.0 |
| R 10/10 | 10.0 | 10.0 | 20.0 |
| R 10/20 | 10.0 | 20.0 | 30.0 |
| R 17/5 | 17.5 | 5.0 | 22.5 |
