In the next three years, Heathkit brought out several more SB-series accessories, including a 2 kilowatt input/1.4 kilowatt output linear amplifier, the SB-220. The SB-400 model transmitter was slightly updated with the newer SB-401 model. The final model in the original SB-series was the SB-303 receiver, a solid state replacement (in a smaller case) for the SB-301 and its earlier sibling, the SB-300 receiver. The 2000 film "Frequency", starring Dennis Quaid and Jim Caviezel, featured a Heathkit SB-301 receiver being used with artistic license as a transceiver (film studio prop), although the SB-301 did not have any transmitter stages in it and was not a transceiver. An SB-302 receiver was never produced (no reason ever given for why the 302 model number was skipped) and some hams who worked at Heath hinted that there was talk of a solid state SB-103 transceiver, but it never made it past the proposal stage.