Magnet Shape: Pot with Threaded Stem / External Thread
Material: Hard Ferrite (Ceramic) and Steel
Coating: Zinc(Zn)       
Grade(Chinese Stardard):         Y30H-1
Magnet ID:              FPET-16-Y30H-Zn  
Detailed magnetic properties data:
Residual Magnetic Flux Density (Br): 3.8-4.0 KGs (mT):  380-400 mT
Intrinsic Coercivity Force (Hcj):    2.89-3.46 KOe    230-275 KA/m
Coercivity Force (Hcb):              2.95-3.64 KOe    235-290 KA/m
Energy Density (BH)max:              3.3-3.8 MGOe     27.0-32.5 KJ/m³
Operating Temperature:               -40 °C to +250 °C
Magnetisation Direction: Axial / Radially magnetized
Pot Magnet Size:
Pot diameter (D): 16 mm
Pot height (H1): 5 mm
Total height (H2): 13.5 mm
Thread (M): M4
Tolerance:         +/-2% mm
Delivery time           7-25 days
Measurements

These pot magnets have a stem with an external screw thread. You can slide the stem, for instance, through a hole and fasten it with a nut.
Distinctive feature: These pot magnets have an external thread.
Principle: The hard ferrite magnets are embedded in a steel pot. The steel pot increases the adhesive force of the magnet on direct contact with a thick iron surface. If there is no direct contact with the counterpart, or if the steel plate is thin, painted or rough, you can strain it much less.
Shear force: The indicated adhesive force was measured perpendicular to the surface to which the magnet should stick. It takes a lot less strength to move the magnet sideways. Therefore, you can strain a pot magnet much less if you use it on a wall as opposed to using it on the ceiling.
Rust: These magnets are not rust-proof and therefore intended for dry indoor use.