I've had this for several weeks now and it works perfectly for the Spectra S2 to allow you to move freely with the pump. I charge it once a day but I'm sure you could go days without charging if needed. I'm also not sure why other reviews say you need a separate connector - just plug the other end of the included cord in (see attached picture).
Fireproof Battery Organizer Storage Case: Waterproof & Explosionproof Safe Bag Fits 210+ Batteries - With Tester BT-168, Carrying Container Bag For AA AAA C D 9V Lithium 3V Holders
49 Review
🔋 EBL Battery Charger Combo: Rechargeable AA Battery 2800mAh (4pcs) and AAA Battery 1100mAh (4pcs) + Charger for AA/AAA/C/D NiMH Batteries
39 Review
Dlyfull LCD Battery Tester - Universal Checker For AA AAA C D 9V CR2032 CR123A & More, 2X AAA Batteries Included
34 Review
LCD Battery Tester For Universal Battery Types - AA, AAA, C, D, 9V, CR2032, CR123A, CR2, CRV3, 2CR5, CRP2, 1.5V/3V Button Cells With Included AAA Battery
29 Review