Doesn't seem to be any QF 4.2 just the same 4.0
urineluck. com /ProductDetails.asp?ProductCode=QFIX

If you've been clean for months you're probably fine to use your own urine. A faint thc line is normal.
Bottles work the best. I don't like the squirt tip. Sometimes it makes noise.
I use a digital thermometer because sometimes the temp can be a little high or low and you can't tell which by feel. So the thermometer is good for double checking.