Tinker & Rasor 6BPicture is for illustrative purposes and shows several different models Copper-copper sulfate half cell electrode 1/4x 7, Pointed Tip Strong body for outdoor use High purity copper and copper sulfateCopper-Copper Sulfate Reference Electrode (1/4x 7, Pointed Tip)Tinker & Rasor offers a complete line of Copper-Copper Sulfate Half Cell Reference Electrodes. All Tinker & Rasor HALF CELLS are made from the most durable materials available, to withstand years of harsh, even severe field use! These fully serviceable Half Cells can be recharged to assure accurate readings for many years.Available models: 2-A Pencil Cell 3-A For Concrete 6-A, 8-A Flat Tips 6-B, 8-B Pointed TipsA tip vs. B tipThe two standard tips available are the A Flat Tip and the B Pointed Tip.Both the Flat and Pointed tips are made to maximize the total surface area of the tip to ensure good contact area with the electrolyte. Mainly a user preference, there is no performance difference between the two types of tip. The A Flat tip may be more versatile, as a flat surface can be useful on a variety of electrolytes, such as soils, liquids and concrete.The B Pointed tip has a cone shape which can be easily buried in soils to ensure good contact with the electrolyte.While the body of the half cell is printed with the tip type, all parts are interchangeable and an A or B tip can be put on any of the Models 6 and 8 reference electrodes.Model 6 vs. Model 8Tinker & Rasor offers the Model 6-A, 6-B and the Model 8-A and 8-B. The difference is in the length of the half cell only. The overall length of the 6 Model is 6 and the 8 Model is 8The Model 8 half cells contain more copper rod, more copper sulfate crystals and more water due to the larger volume of the tube.Model 3-A Fat BoyThe Model 3-A Fat Boy reference electrode has been designed specifically for use on concrete. The large surface area, 3 diameter, h