Two tiny receivers with the same brand logo can use different wireless systems. Replacing a lost dongle therefore starts with identifying the mouse or keyboard, not choosing a receiver that looks similar in a photograph.

Record the device identity

Read the model and product information on the underside or in the manufacturer's support page. Check any receiver-family symbol on the device itself. Keep that information separate from the marketing name, because similar product names can cover different versions.

Logitech states that Logi Bolt devices cannot pair with Unifying receivers, and Unifying devices cannot pair with Bolt receivers. Its replacement guide uses the corresponding logos to help identify compatibility and directs owners of other receiver types to support.

Do not assume that every Logitech wireless product belongs to either family. A gaming or model-specific receiver may have a different replacement process. Likewise, Bluetooth capability does not prove compatibility with a particular USB receiver.

Confirm pairing support before buying

Use the exact model's current support instructions to confirm both the replacement part and the supported pairing software. Avoid old third-party utility downloads. Logitech's support pages now mark several legacy utilities as unsupported, so a years-old tutorial may describe a route that is no longer maintained.

If the device has a working Bluetooth connection, keep it available while checking the receiver option. There is no need to erase a useful pairing merely to identify a replacement part. Record any multi-device channel that you intend to use for the new connection.

After obtaining a confirmed compatible receiver, pair according to the current instructions and test ordinary movement or typing. Then test reconnection after sleep and a normal restart. Label the receiver and device together if several similar sets share the workplace.

Keep the old model information with the replacement record. That small identification step prevents the next lost dongle from becoming another round of trial purchases and unexplained pairing failures.

Sources: Logitech Bolt and Unifying compatibility; Logitech replacement-receiver identification.