The ornamental design for a carseatholder, as shown and described.
FIG. 1 is a top perspective view of a car seat holder showing my new design;
FIG. 2 is a bottom perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a left elevated view thereof;
FIG. 8 is a right elevated view thereof;
FIG. 9 is a top perspective view thereof, showing the car seat holder in an alternate, expanded configuration; and,
FIG. 10 is a top perspective view of a car seat holder used as support for an infant car seat.
The broken lines showing of a strap in FIG. 1-9 and the broken lines showing of padding on the grips in FIG. 1-4, FIG. 6, and FIG. 9, and the broken lines showing of an infant car seat in FIG. 10 are included for the purpose of showing environmental structure and form no part of the claimed design.