Tracking your bitch's temperature in the days run up to her due date is a great way to predict the start of labor.  This kit explains and provides the tools to identify a temperature drop, which is an indicator that the start of labor is imminent.  As a breeder myself I alway use this technique and recommend it to all my clients. 

Pack includes: Eco Rigid Thermometer,Temperature Chart & 5 X 5ml Light Lube Lubricating Jelly Sachets

Eco Rigid Thermometer
Details:  Rigid Tip, Reads in 60 Seconds, Centigrade & Fahrenheit, Auto Shut Off, 1.5v Button Battery, Bleeper Function When Peak Temperature Reached, Low battery Indicated & Water resistant & Last memory reading

Temperature Chart

By recording your bitch's temperature you can identify the drop that usually happens before the commencement of labor.  It can also identify any abnormally high temperature reading, which might require the attention of your vet.

5ml Light Lube Lubricating Jelly Sachets
Pasante Light Lube is a water based lubricant for gentle lubrication.  Non-Spermicidale, Clear, Odourless Non-greasy, Non-Staining & Longer Lasting