Mockingbird Single-to-Double 3.0 vs Mountain Buggy Cosmopolitan
The Single-to-Double 3.0 is 2 lb lighter. The Single-to-Double 3.0 lists for $50.99 less.
Only the differences are shown.
| Mockingbird Single-to-Double 3.0 | Mountain Buggy Cosmopolitan | |
|---|---|---|
| List price | $549Lowest price | $599.99 |
| Weight | 28 lbLightest | 30 lb |
| Folded size | 18 × 25.5 × 34 in9.0 cu ft | Not listed |
| Open size | 33 × 25.5 × 40 in | Not listed |
| Seat holds up to | 50 lb | 55 lbHolds the most |
| Child height up to | 42 in | Not listed |
| From birth? | Yes, with bassinet (sold separately) | Yes, seat lies flat |
| Bassinet holds up to | 20 lb | Not listed |
| Seat recline | Not listed | Flat |
| Seat faces you or the world | Yes | Yes |
| One-hand fold | Yes | Yes |
| Stands when folded | Yes | Yes |
| Fits airline overhead bin | No | Not listed |
| Converts to a double | Yes | No |
| Basket | 25 lb, XL basket; seat-back and in-seat pockets | Not listed |
| Car seats | 50+ infant car seat models with the Car Seat Adapter (sold separately) | Not listed |
| Car seat adapters | Mockingbird Car Seat Adapter (50+ infant seats) | TS21 adapter (phil&teds/Mountain Buggy, Maxi-Cosi, Cybex) |
| Brake | Not listed | Hand brake |
| In the box | Frame, wheels, seat with canopy, LegShade and child bar (2nd Seat Kit 3.0 sold separately, $175) | Not listed |
| Sold as a travel system | Single-to-Double Stroller 3.0 + Bassinet Bundle ($699) | Not listed |
| Released | 2026 | Not listed |
| Handlebar height | Adjustable | Adjustable |
| Wheels and suspension | Never-flat wheels with all-wheel suspension; front wheels lock | Rear air-filled tires, puncture-proof 360° swivel front tires, all-round suspension |
| Canopy | Extendable UPF 50+, height-adjustable, with leg shade | Not listed |
Mockingbird Single-to-Double 3.0
A single stroller that turns into a double when you add a second seat kit, aimed at families expecting a second child. Seat faces either way and has five recline positions.
- Grows from single to double with a second seat kit
- One-hand fold that stands on its own
- Reversible seat with 5 recline positions
- Newborn use needs a separately sold bassinet, insert or car seat adapter
- About 36 lb as a double
Single-to-Double 3.0 or Cosmopolitan?
Answers come from each maker's published specs. Safety and health questions link to the agency or medical source.
Which is lighter, the Single-to-Double 3.0 or the Cosmopolitan?
The Mockingbird Single-to-Double 3.0 weighs 28 lb, 2 lb less than the Mountain Buggy Cosmopolitan (30 lb).
Is the Single-to-Double 3.0 cheaper than the Cosmopolitan?
Yes. The Single-to-Double 3.0 lists for $549 and the Cosmopolitan for $599.99, a $50.99 difference. Sale prices change often.
Can both be used from birth?
Single-to-Double 3.0: Yes, with bassinet (sold separately). Cosmopolitan: Yes, seat lies flat.
Which one lasts longer?
The Cosmopolitan seat holds more: 55 lb versus 50 lb.
Still wondering? Write to us at hello@cribpicks.com and we'll look it up.