Go-Cal Replacent Battery Pack Back Catalog number: 811-9917-03 Manufacturer: SENSIDYNE Availability: In the manufacturer's stock Price on request - + Recommended 811-0501-01 Flow Monitoring Software Kit (Software, Cable, & M Price on request 298-0027-01 Charger, Smart Lithium Ion 100 to 240VAC for Nephe Price on request 385-0117-01 Tri-pod mounting bracket for Nephelometer (Tri-pod Price on request