Homemade Sausage Making

Looking at a hanna ph meter top left in picture. Can anyone enligten me as to why the meter is $160 but the spear tip is $356 Is there anything special about it and is it needed?

Basic pH-meter (left top corner) comes with that glassy spear. It is enough to make measurements even in salami. In some more hard meats or cheese it is good idea to make a small packet with tip of knife before inserting spear. Expensive spear has special sleeve over glassy spear and it is semi-drilled
in hard surfaces. Other words - it is specialty spear and not needed for "hobbyists". I have used that inexpensive Hanna meter and IMHO - it is very good, very handy a and accurate for our meat processes.

Awesome thanks