It is highly likely you are looking for the Uniden Bearcat BC125AT, which is widely sold as a "Pro44" variant (or under similar branding like "Pro-Scan" or generic "Police Scanner" labels), or you may be referring to the RadioShack Pro-44 (an older, vintage model).
Memory Loss: If the scanner forgets its programmed channels when the batteries die, it may have a depleted internal backup capacitor; try leaving the scanner powered on for 24 hours to recharge it. 3+ Easy Ways to Program Your Police Scanner Today netset pro44 scanner manual link
Finding the official Netset PRO-44 scanner manual can be tricky because this device is a rebadged version of the RadioShack / Realistic PRO-44 (catalog number 20-304). While the Netset branding was used for international markets, the internal components and operating procedures are identical to the popular Realistic model. Direct Manual Link It is highly likely you are looking for
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I managed to locate a direct digital copy for anyone who needs it. Post on Reddit (r/hardware
If you have an older, boxy scanner, you might be looking for the RadioShack Pro-44.