Milwaukee Instruments, MA918B/1, Refillable Combination pH Probe for SoilThe MA918B/1 is a lab grade refillable glass electrode with a conic tip designed for measurements in soil.Features:The MA918B/1 probe makes pH testing easy and fast.The triple reference design reduces risk of clogging with the reference cell physically separated from the intermediate electrolyte.The MA918B/1 is refillable with MA9011 3.5M KCl+AgCl electrolyte. This solution is sliver free. Sliver can cause silver precipitate to form at the junction resulting in clogging. Clogging causes erratic and slow readings. The ability to refill the electrolyte also extends the life of the electrode. The glass body is easily cleaned and resistant to chemicals.The conic design of the tip provides the largest possible surface area for faster readings and is well suited for testing in soft soils.