Is this what you mean?
If so, run away, run far far away as fast as you can!
Seriously, this is an absolute LAST RESORT for travel only: frequent taxicab, etc. for the child who doesn't fit other options.... This seat does perform well in frontal crash tests because kiddo sits so low + far back (kiddo's head is well within the maximum 28" of allowable forward movement) however it is nearly impossible to install correctly in any vehicle (must have less than 1" at the belt path) & the harness is nearly impossible to adjust to correct size
The only use I found for this seat was for kiddo to take ownership over car safety by letting her buckle a dolly into it before I buckled her into her own (much safer more dedicated) traditional carseat.
Let's start at the beginning to see if we can find safer options for your situation
What is each child's age, weight, height & what is the vehicle year, make, model? Also, what is your budget?