Shooting a basic 18-70 3.5-4.5, Can't decide between a prime 50mm or putting my money towards a 70-200 or 105 f/2dc or the 105 macro. Somewhat leaning towards the 105...
the whole drink "x' amount of water and flush your system out holds little validity.
If you smoked within a month, chances are you will fail.
External urine is your only safe guaranteed choice.
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