There are generally two types of digital probes; Thermistor and Thermocouple. They are both highly accurate but the Thermocouple is way much faster in it's reading (usually less than 5 seconds), has a thinner probe, and can obtain an accurate reading by only being inserted 1/4". The thermistor has a thick probe, longer response time (generally 10 seconds or greater), and must be inserted at least 1/2" for an accurate reading. Which is still great for thin cuts of meat.
Hopefully Pens is monitoring, and he can give you more accurate information. What I believe is most important; is weather the unit you are building is compatible with the thermistor or thermocouple style. If it is compatible with the thermocouple, the pro series probes from Thermoworks
are great probes, the end where the wire enters the probe is well sealed, and they are price about the same as Maverick's replacement probes.