Note: The following info pertains to car seats currently sold in the US. Always refer to your child seat & vehicle owner’s manuals.
Rear-facing infant seats usually come with a base.
LOWER ANCHOR STRAP: permanently attached to the base
TETHER STRAP: none currently sold in the US use a tether
NOTE: When using the infant seat without the base, you will need to use the vehicle’s seat belt to secure the seat – as the lower anchor strap is permanently attached to the base (and should not be removed).
All infant seats currently sold in the US allow you to use the carrier without the base.
Sometimes rear-facing infant seats come by themselves (i.e. without a base) – these are typically distributed to families who can not otherwise afford a car seat. The information below is for carriers that come without a base (for carriers that come with a base, see above info)
LOWER ANCHOR STRAP: permanently attached to the carrier
TETHER STRAP: no infant seats currently sold in the US use a tether
LOWER ANCHOR STRAP: permanently attached to the seat.
Many convertible seats have one long lower anchor strap with a connector on either end, while others have 2 separate lower anchor straps each with a connector on the end. Some convertible seats have a separate lower anchor strap for rear-facing & forward facing (ex. Graco My Ride 65).
**Always make sure the lower anchor strap is routed in the proper place for the direction the seat is facing. Typically the lower anchor strap goes under the child’s legs for rear-facing and behind the child’s back for forward-facing. Nearly all seats require you to make some change in the lower anchor strap when the seat goes from rear-facing to forward-facing.
TETHER STRAP: Most convertible seats do not use the tether rear-facing. ALL convertible seats use the tether forward-facing.
***Remember: While the lower anchors are used INSTEAD of the vehicle’s safety belt to secure the child safety seat to the vehicle, tethers are used IN ADDITION to the lower anchors OR the vehicle’s safety belt to secure a forward-facing (and some rear-facing) child safety seat to the vehicle.
For lots more information on tethering a rear-facing convertible seat, see here.
LOWER ANCHOR STRAP: permanently attached to the seat.
TETHER STRAP: All combination seats come with a tether. While the tether is technically optional on most combination seats (but should always be used whenever possible as it decreases how far the child’s head moves forward by up to 8 inches), there are a few that require the tether. For example, the IMMI Go requires the tether at all times, while the Britax Frontier 85 requires it for children weighing more than 65 pounds who are using the 5 point harness.
***Remember: While the lower anchors are used INSTEAD of the vehicle’s safety belt to secure the child safety seat to the vehicle, tethers are used IN
ADDITION to the lower anchors OR the vehicle’s safety belt to secure a forward-facing (and some rear-facing) child safety seat to the vehicle.
Many, but not all, combination seats allow the use of the lower anchors and tether strap to secure the seat to the vehicle while the seat is being used in the booster mode (i.e. the child is using the vehicle’s shoulder/lap belt across them). Read the manual to your child’s seat to see if it is allowed.
TETHER STRAP: None of the high-back boosters (that weren’t part of a combination seat) currently come with a tether strap.
LOWER ANCHOR STRAP: Most booster seats do not come with lower anchor connectors – however, some do. the few that do most often have rigid lower anchor connectors (instead of a flexible lower anchor strap as is found on nearly every other type of car seat). See close-up drawing at left of a rigid lower anchor connector.
The following high-back boosters allow the use of the lower anchors:
TETHER STRAP: No backless boosters use a tether strap.
LOWER ANCHOR STRAP: Most do not have a lower anchor strap/connector, but some do.
The following backless boosters allow the use of the lower anchors:
LOWER ANCHOR STRAP: Does not have a lower anchor strap
TETHER STRAP: tether must be used when using a lap-only belt, and may be used for extra support when using a shoulder belt. Note: not all versions come with a tether strap – so check before ordering if you plan to use this product with a lap belt.