Medical Lockbox Utilizing a medical lockbox will lower costs, improve cash flow, virtually eliminate the risk of fraud and make it possible to search and view checks, EOBs, payment coupons and correspondence instantly. Medical practices have unique requirements and SIS NW’s lockbox solution is custom tailored to the needs of medical practices. Most bank lockbox services start and stop with the deposit of checks. SIS NW’s solution is customized to the unique needs of medical providers.