What is replacement part for E51FLT2

The model E51FLT2 disappeared many years ago and was replaced by the model E51ALT2.  The E51FLT2 had output current ratings of up to 1 amp but did not have short circuit protection.  The E51ALT2 has short circuit protection but reduces the maximum load current rating to ½ amp.  So, unless they are switching more than ½ amp, we would say the E51ALT2 is a direct replacement.  If they are switching more than ½ amp, there is no direct replacement but could consider the model E51CLT2 but they would have to re-wire the installation, adding a neutral wire.