--- product_id: 385205663 title: "OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus)" brand: "osalo" price: "€ 3.63" currency: EUR in_stock: true url: https://www.desertcart.pt/products/385205663-osalo-scientific-calculator-written-display-solar-powered-ultra-light-engineering store_origin: PT region: Portugal --- # 417 advanced functions ultra-light 120g design dual solar & battery power OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) **Brand:** osalo **Price:** € 3.63 **Availability:** ✅ In Stock ## Summary > 🔬 Elevate your calculations—where precision meets portability! ## Quick Answers - **What is this?** OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) by osalo - **How much does it cost?** € 3.63 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.pt](https://www.desertcart.pt/products/385205663-osalo-scientific-calculator-written-display-solar-powered-ultra-light-engineering) ## Best For - osalo enthusiasts ## Why This Product - Trusted osalo brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Ultra-Light & Portable Design:** Sleek matte silver with blue back, weighing just 120g—perfect for on-the-go professionals and students alike. - • **Master 417 Functions with Ease:** Covers every scientific need for university-level calculations, ensuring you never miss a formula. - • **Textbook-Style Written Display:** Input expressions exactly as in textbooks for effortless verification and error-free results. - • **Dual Power for Unstoppable Performance:** Solar plus battery power guarantees your calculator stays on during long study sessions—no interruptions. - • **Ergonomic Plastic Keys with Clear Print:** Distinct key shapes and crisp lettering provide a comfortable, precise typing experience every time. ## Overview The OSALO OS-991ES Plus is a solar-powered scientific calculator featuring 417 functions and a textbook-style written display. Designed for university students and professionals, it combines dual power sources for reliability, ultra-light portability at 120g, and ergonomic plastic keys for comfortable use. Its advanced functionality and user-friendly interface make it an essential tool for mastering complex calculations anywhere. ## Description ## Features - 【417 Functions Scientific Calculator】The scientific calculator has 417 functions and covers the most scientific functions what college students need to use at university. Reading instruction attached will help you know how to use and find these functions. - 【Written Display Scientific Calculator】Input expressions and arithmetic operations same as written form in the textbook, which is more easy to read than traditional calculators. Written display expression same as textbook,convenient for students to check the calculation process and results. - 【Dual Power Source Electronic Calculator】Solar and battery,double safe uninterruptible power,environmental protection and energy saving advantages. - 【Ultra-light & Portable】Nice color matching: Matte silver panel & blue back; Weight: 120g; Size: 162 x 80 x 14(mm)/6.4 x 3.2 x 0.6 (inch);Material: ABS plastic. Convenient to carry it outside and hold it on one hand. - 【Plastic Keys】Use high quality plastic keys,and make keys in different area have different shape, to give you the most comfortable experience. Letters printed on keys are super clear. ## Technical Specifications | Specification | Value | |---------------|-------| | Brand | OSALO | | Manufacturer | OSALO | | Model | OS-991ES PLUS | | Model Name | OS 991ES Plus | | Package Dimensions | 19.1 x 8.51 x 3.71 cm; 180 g | | Batteries | 1 LR44 batteries required. (included) | | Item model number | OS-991ES PLUS | | Standing screen display size | 162 Millimetres | | Display Type | LCD | | Power Source | Solar Powered | | Batteries Included | Yes | | Batteries Required | Yes | | Battery cell composition | Alkaline | | Material | abs plastic | | Includes Rechargeable Battery | No | | Manufacturer | OSALO | | Item Weight | 180 g | ## Product Details - **Brand:** OSALO - **Colour:** Silver - **Calculator Type:** Engineering/Scientific, Financial - **Power Source:** Solar Powered - **Screen Size:** 162 Millimetres ## Images ![OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) - Image 1](https://m.media-amazon.com/images/I/716al1zwHmL.jpg) ![OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) - Image 2](https://m.media-amazon.com/images/I/61hZd74e4xL.jpg) ![OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) - Image 3](https://m.media-amazon.com/images/I/61CiIg6XuBL.jpg) ![OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) - Image 4](https://m.media-amazon.com/images/I/618hiXsB2WL.jpg) ![OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) - Image 5](https://m.media-amazon.com/images/I/613bdOBU7pL.jpg) ## Questions & Answers **Q: Can I use it for high school and college too?** A: It's a good choice for high school and college students learning General Math, Trigonometry, Statistics, Algebra I and II, Calculus, Engineering, Physics. **Q: How loud are the buttons?** A: The conductive adhesive material used in OS-991ES PLUS is silica gel, made of high-quality silicone oil, and the carbon dots of the buttons have high sensitivity. They work almost silently. **Q: Is this a TI-34 calculator?** A: No, the TI stands for Texas Instruments. **Q: Is this a programmable calculator?** A: It is not programmable. ## Frequently Bought Together - OSALO Scientific Calculator Written Display Solar Powered Ultra-Light Engineering Calculator for School University (OS-991ES Plus) - BIC Brite Liner - Pack of 5, Multi Color --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.pt/products/385205663-osalo-scientific-calculator-written-display-solar-powered-ultra-light-engineering](https://www.desertcart.pt/products/385205663-osalo-scientific-calculator-written-display-solar-powered-ultra-light-engineering) --- *Product available on Desertcart Portugal* *Store origin: PT* *Last updated: 2026-06-20*