Is the Kab Speedstrobe necessary with the VPI SDS?

Is it necessary (in order to accurately pinpoint the exact 33 and 1/3 platter speed) to purchase something like a KAB SPEEDSTROBE after buying the VPI SDS?
You still have to calibrate the SDS. Same with Walker Audio's motor controller. As indicated above, it's for that calibration step that you use the KAB disc and strobe. Then it's simply a question of how long the motor controller will retain that calibration before drifting.
If you live outside of the USA where you have 50hz, the VPI supplied strobe is USELESS. No mention of that in the manual thou.
The KAB and strobe is very easy to use.
I agree Shane. Its got me beat why Harry doesn't supply a strobe disc that includes 50Hz markings - at least for export to England/Australia etc. The strobe disc that came with my SDS is the same one supplied 14yrs previously with my TNT - totally useless with 50hz mains.
The KAB strobe is brilliant. Maybe Harry should offer it as an option?
Strobe??...Was there supposed to be one in the SDS box?..Mine just contained the strobe disc and the SDS.Has to buy one later...
Ok, now you guys have me wondering. I just ordered my SDS from my dealer over the holidays and he made no mention of needing a seperate strobe or disc saying "it comes with all you need".

Is one included with the SDS thats "ok" to use? Does the KAB just make things more exact and easier to set up?