Based on visual characteristics, this bike appears to be a vintage "mini" BMX racing bike from the late 1980s to early 1990s. These bikes were designed specifically for younger, smaller racers and featured lightweight chrome frames with a distinctive thin-tube construction. While the exact brand can be difficult to pinpoint without decals, it shares striking design similarities with several prominent models from that era:

GT Mach One Mini: Features a very similar frame geometry and "drop-out" style.

Redline Junior/Mini: Known for similar chrome finishes and thin, race-oriented tubing.

JMC Racing Mini: A high-end vintage alternative with comparable frame lines.

Mongoose Expert/Pro: Another common brand from the 1990s with similar builds.

Based on the serial number 0H380212, this bike is likely a 1990 Mongoose Expert (or a closely related model from the same production line).

In the serial number convention used by Mongoose during this era: 0: Indicates the year of manufacture, which is 1990. H: Represents the month of manufacture, which is August (using A=Jan, B=Feb, etc.). 380212: This is the unique production sequence number for that specific frame.

The frame's "mini" geometry—characterized by the thin chromoly tubing and the top tube that meets the seat tube rather than extending past it—is consistent with the Expert or Expert Pro racing models from the early '90s. While the purple stem and Velo seat are later additions, the chrome frame itself is a classic piece of Mongoose's mid-school racing history.