The use of nitrogen-vacancy (NV) spins in diamond for magnetic imaging is a powerful technique for measuring magnetic order at the sub-microscopic scale. This technique is increasingly used for the study of 2D materials as it offers high sensitivity combined with high spatial resolution. One challenge is to position the NV centers at a precisely defined distance in the nanometer range to the target material. This is the only way to detect the very small magnetic fields generated by magnetic monolayers of some 2D materials. Toeno van der Sar's group at TU Delft has published an interesting paper on this. [1] The group has developed a "dry transfer" technique to transfer a diamond micromembrane with NV centers directly onto a CrSBr sample.  CrSBr is an antiferromagnetic 2D material. This technique achieves a close contact between diamond and sample, which is crucial for the detection of weak magnetic fields. The direct contact between the diamond membrane and the 2D magnet is one of the main advantages of this technique. The method minimizes the risk of contamination at the interface and can be used in an inert gas atmosphere, making it suitable for air-sensitive 2D magnetic materials. Due to the proximity of the NV sensors in the diamond to the sample, the magnetic stray fields of the CrSBr could be spatially resolved, which only occur when the thickness of the CrSBr changes by an odd number of layers. A monolayer magnetization of MCSB = 0.46(2) T was measured from the magnetic stray field of a single uncompensated ferromagnetic layer in CrSBr without the need to exfoliate monolayer crystals or apply large external magnetic fields.