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 |