The magnetic field strength (lines of flux per square inch) are as follows: 

On the surface of a 42 Mega Gauss Oersteds (42 MGO) rated magnet,  the magnetic field strength is 13,000 gauss.* This strength falls off quickly as the distance increases.  We try to position the magnet as close to the deck as possible given the constraints of the magnetic cylinders and deck design.  The VP 710F D4 and D6 deck design places the magnetic cylinder closer to the deck than the even more powerful VP 710S so it appears to be stronger at the deck surface.  However it is not able to project this field as far as the VP 710S. 

The MGO rating for the magnets used in the following tumble stirrers are listed as superscripts after the product numbers
(42, 45, or 48 )

To put these numbers in perspective from a safety standpoint - the gauss level at the surface of a Qualcomm dual band cellular phone held against your ear is 25 gauss and a Verizon flip cellular phone (LG) is 48 gauss.  Both of these cell phones exceed the magnetic field strength present 7" from the cylinder guard of the of a VP 708A Vortex Lateral Tumble Stirrer. 

*Note that distance between the magnet surface and the surface of the deck varies for each magnetic tumble stirrer design and thus the gauss levels at the surface of the deck varies.  Note that the VP 710E-1, VP 710C-1 and the VP 710SM3P both use the stronger 48 MGO magnets

Note that the VP 710SC (custom) uses a longer magnet than the VP 710S and therefore will project the field farther.

Noted that the magnets used in the VP 710S and VP 710SC are rated at 45 MGO and the VP 710S-2 magnets are 48 MGO.

The Above Graph is also available with a linear scale here

The VP 710A with it's multiple magnetic cylinders has less magnetic "bloom" because the adjacent magnetic fields pull it down.

STIR ELEMENT DATA

To see how these gauss reading translate into practical data in Tumbling Stir Elements see the following link.

HEALTH CONCERN

Makers of cardiac pacemakers have placed magnetic switches in them that can be activated when the pacemaker is in a 5 gauss magnetic field.  The critical 5 gauss line varies from 5.5" to 22.8" above the deck or cylinder guard with our stirrers. The graph indicates that the magnetic field falls off very fast with distance.  However as a safety factor we recommend that people with pacemakers keep at least 36" or 91 cm from the Alligator Vertical Tumble Stirrers and the Vortex Lateral Tumble Stirrer.  The cardiac pacemaker company Medtronic has a web page that discusses the 5 gauss line in more detail.