what kind of coin is this?

ive tried to search the cataloged but I cant figure it out. about the size of a dime but very light weight. can barely make out the letters “LT within a word on the backside

IV. century roman nummus. The reverse text is partially readable. ‘FEL TEMP’, which is part of ‘FEL TEMP REPARATIO’, a common type of reverse: https://en.numista.com/catalogue/index.php?e=rome&r=&st=1-2&cat=y&im1=&im2=&ru=&ie=&ca=3&no=&v=&a=&dg=&i=*fel+temp+reparatio*&b=&m=np&f=&t=&t2=&w=&mt=&u=&g=&c=&wi=&sw=&p=3

The revere image is probably the fallen horseman type (like this: N#70142 or N#190856). It is also an ‘M’ or ‘N’ in the field, beside one of the figures.
Neither the name of the emperor (on the obverse, around the head) or the mint (on the bottom of the reverse) are readable.